A comprehensive answer is going to require getting into the question of "what is a language?" The answer to this is more determined by culture and politics, moreso than a structural analysis of the language itself.
Nonetheless, I'm quite sure the answer is "no."
It seems that Afrikaans achieved official recognition by South Africa in 1925. Since this was recognition of existing everyday usage, this means that the language is "really" much older. I'm not sure how old, but fine, we'll use 1925 as the baseline. Afrikaans is certainly no younger than 97 years. It seems there is evidence of its use as the primary method of communication dating back to the mid-1800's.
I'll examine a couple of different definitions of "language" around the margins, before finding younger direct comparisons to Afrikaans.
One common requirement for something to be a "real" language is that there are native speakers. That is to say, people who grew up from childhood speaking that as their primary language at home. (This generally excludes many "official" languages that are sufficiently far-away from the actual spoken language of their community. A common example is Finnish, where version taught in schools and used in news broadcasts is not what people actually speak.)
Under this definition, Klingon is a real language. Yes, from Star Trek. There are dozens of people that speak it as a second language, but one guy actually raised his kid to be bilingual in English and Klingon. I've heard mixed reports on whether the courts determined this to be child abuse. Klingon had no existence whatsoever before 1967, and only became developed-enough to speak in sentences in 1984, making it younger than Afrikaans by a good deal.
Klingon, of course, is a constructed language rather than a natural on, and does not have an associated community or nationality (outside of fiction). Here's another example to chew on: Modern Hebrew. As the saying goes, "a language is a dialect with a flag and an army." Hebrew, being the daily-life language of Israel, meets that definition and so has a stronger claim to being a "real" language compared to Klingon.
For a long period, Hebrew was a scriptural language but not one used by communities for day-to-day activities. By most official counts it was dead, its ceremonial use notwithstanding. Compare to how Latin is considered dead despite continuing use in the Vatican. It was intermittently revived as a literary language, but only started becoming used as a language for everyday speech starting in the late 1800's. As far as I can tell, it post-dates the emergence of Afrikaans by a few decades.
Still, Hebrew is technically reviving a language with a much longer history. Modern Hebrew is a bit different than scriptural Hebrew, but probably most people will consider it older in some meaningful sense.
Ok, now to more direct comparisons.
Afrikaans is an example of a linguistic phenomenon called a creole. A community inhabited by two cultures with different languages often develops something called a pidgin, which is a simplified mish-mash of two languages of two languages for the purposes of communication. If the community persists, a new generation of kids may be raised speaking that mix as their primary language. This new language is called a creole, and is generally more consistent and structured than its pidgin predecessor, since it has a bigger job to do (i.e. the entire breadth of human experience). The degree to which its grammar borrows from either parent language varies wildly.
Not to read too much into the question, but I'm guessing that you thought Afrikaans' background more unique that it actually is because you didn't realize how common creoles are. They're relatively common, because there are a large number of situations where one language-group will enter into another language-group's community and stay there. (Someone more versed in colonialism can speak to that better.)
While I don't have a definite answer to the date of the specific origins of Afrikaans, I can find some creoles that are probably younger.
This list is not exhaustive, it's just what I can pull together now before I have to leave.
In retrospect, all my examples are from Oceania or thereabouts. I expect this is because many creoles emerge from colonization (though not all), and that region's history of colonization is more recent than South Africa's.
Source: Most of my general knowledge on this topic probably comes from The Power of Babel by John McWorter. Specific supporting details pulled from Wikipedia.
Short answer: Almost certainly not.
So this is a rare case of me having enough knowledge to contribute to this topic, I hope. I have an undergraduate degree in Linguistics and though my specific focus was mainly on semantic development of terms within English I do think it qualifies me to answer this question.
So what is a language and how does one come to be? So this is a really difficult question of course. As a biologist might have trouble offering one comprehensive definition of life, a linguist has trouble offering a single comprehensive definition of a language. At the risk of coming off like this is the definition, allow me to offer a definition: A language is the structured speech^1 used by a certain group of people to structure their thought and communicate among themselves. A more pithy definition is that a Language is a Dialect with an Army and a Navy. This reflects the fact that a position on what group of speech varieties is and is not a separate language is inherently a political statement.
When did Afrikaans "become a language"? When did it stop being a variety of Dutch? The answer is a much more political question than a linguistic one. Similarly, why is American English still considered the same language as broad Geordie, when a given speaker of each variety will almost certainly not be able to communicate effectively with the other in their native dialect? The two dialects are separated by a similar level of time-depth. Why is Arabic one language whilst Romance is several dozen?
So I will not attempt to answer this specific question. I will not speak in terms of when something came to be a unique language. But we can consider when something came to be considered a unique language. In these terms, the answer is still not Afrikaans. As I understand, Romanian and Moldovan were briefly considered two languages, though the parliament of Moldova later declared that Moldovan and Romanian were two names for the same language. Linguists often speak of Serbo-Croatian as one language, where particular identification with Serbian or Croatian or Bosnian linguistic identity is tied very closely to ethnoreligious identity. A case could be made that these languages have torn themselves into separate entities much more recently than did Afrikaans. I do not desire to claim that either of these is the "youngest" language, but both are younger than Afrikaans.
Some mention must also be made of constructed languages. Constructed languages, unlike naturalistic languages, are created by people for one purpose or another rather than arising naturally from human communicative needs. If they are considered, then some post on r/Conlangs is probably the youngest language. Until tomorrow. ETA: It is also worth noting that most standard, formalized varieties of a given language are in a sense also conlangs. MSA, Mandarin, Italian, German, French - all of these are constructed varieties of a group of naturalistic languages, designed to serve a sociopolitical purpose (usually a nationalist one).
I would lend my guess to the youngest naturalistic language in the sense of having arisen in recent history being Nicaraguan Sign Language, which arose in the 1980s when Deaf Nicaraguan children were all sent to one school and began spontaneously signing. It bears no known linguistic phylogeny compared to other sign languages which have easily identifiable historical roots, ASL being descended from French Sign Language by way of Martha's Vineyard Sign for example if i remember correctly.