India's nuclear test (in 1974, not 1975) was of what it called a "Peaceful Nuclear Explosive." Now obviously nobody saw a large difference between that and a nuclear device you could use for a weapon, except that India did not deploy said nuclear warheads on missiles or anywhere else. (This is what is called in the literature the "force posture" of a state — if your force posture doesn't match your stated policy, then nobody believes it. If it does, then they might.) This of course was not viewed favorably by Pakistan, and they did, predictably, begin a nuclear weapons program almost immediately after the Indian test. But it should be clear that India was not overtly threatening Pakistan with nuclear weapons after 1974, even if the future possibility was very evident.

Pakistan's nuclear program was relatively slow going, because they were (and are) an absurdly poor country to have a (very expensive) program like that which is required to develop nuclear weapons. To put it into perspective, Pakistan's GDP in 1975 was about 8 billion USD. India's was over 10X more than that. The Manhattan Project, by comparison, cost $2 billion dollars... in 1945. In 1975 that would be about 6-10 billion USD. Which is just to say that this was a significant expenditure for Pakistan, and when its Prime Minister at the time said, "If India builds the bomb, we will eat grass or leaves, even go even go hungry, but we will get one of our own... We have no other choice.," he wasn't totally exaggerating about the austerity that would be required.

A nuclear weapons program requires considerable technical expertise. I am not really talking about "secrets," e.g., things you can write down, but those do matter in some places. It requires people who are trained in the myriad of different scientific, technological, and industrial problems that need to be solved, it requires infrastructure to produce the many specialized components and materials that are used to develop the fuel for the weapons and the military applications of the weapons, and it requires being able to do these things freely. Pakistan struggled with each and every one of these conditions, especially the latter: Pakistan was a close US ally and there was considerable pressure put on it not to "go nuclear" by the US, even as Pakistan managed to avoid much scrutiny for the very reason that it was a US ally, and became an even closer one during the Soviet-Afghan War (1979-1989) when it served as the launching point and arms/money funnel for the US to the mujahideen.

They had some help, inadvertently, from the Dutch uranium enrichment company URENCO, from which the Pakistani metallurgist A.Q. Khan smuggled out plans for advanced gaseous centrifuges. But it still took a lot of resources, and work, to put such things into practice, and to build up the human capital needed to do it all safely. And as a result of the Indian test in 1974, the international community was starting to put immense pressure on nascent states not to nuclearize, and to crack down on the trafficking of sensitive equipment. (Pakistan did have some non-inadvertent help: the People's Republic of China gave them some amount of assistance, including help on weaponizing their warhead. The details of this are somewhat murky.)

Anyway — to get back to the main thrust, it takes time to roll out a program this large in any state, if you are going from essentially zero, and especially in a poor state. Despite all of this, Pakistan is now thought to have been likely "nuclear capable" as early as 1986. They did not, however, test or deploy said weapons until 1998, when India (for reasons only somewhat relating to Pakistan) tested its own "weaponized" versions of nuclear warheads, and began saying it would deploy them. Which is to say, Pakistan and India, for awhile, both "had nukes," but neither were deploying or testing them (beyond India's "peaceful" test), until they both started doing it.

That means the Pakistani program is less like 24 years to the bomb, and more like 12 years to the bomb, which is relatively slow (India was more like 7 years, but had more money and more technical infrastructure to start with), but that is sort of par for the course for a poor state trying to do it clandestinely. They did not wait, is I suppose the conclusion here.

On Pakistan and India's approaches to the bomb generally, Jeffrey Richelson's Spying on the Bomb has a nice comparative set of chapters (and also looks into other states of similar economic size, like Taiwan, who also had a nuclear program but was not successful), and also spends a lot of time on the A.Q. Khan issue. The current best book on the Pakistani nuclear program is probably Feroz Khan's Eating Grass.