Since the events of Ragnarok are spelled out in very clear terms about what will happen and who will kill who and how everything will transpire... does that mean that the vikings believed in some way that fate was determined for them and that you were merely along for the ride? Probably vastly oversimplifying things based on limited knowledge but genuinely curious.
Let us first start with the main sources of the Norse mythology: Poetic and prose Eddas. Both were written around the same time, that is the first half of the 13th century, out of which one was definitely written by a christian scholar 200 years after the Christianity became the official religion on Iceland. You see the issue here? 200 years is a long time.
It is almost impossible to say which parts of the mythos are genuine, original components of the ancient religion, which parts are folk stories added after the decline, and which parts are embellishments of the christian authors who wrote them down.
However, you're asking whether the fate played an important role in the mythos - and based on what we're left with, the answer is yes, it did. There are female beings called "Norns" who spin the wheel of time and determine the fate of all. There are similar beings in other religions, like the Greek Fates who serve the same function.
No one can say for certain what your typical 10th century viking really believed in, and whether he even knew about the Fates (Norns) and Ragnarok, or whether these are pure greco-christian additions.
I might be wrong, of course, so if there is anyone with a thorough knowledge of old sagas, please, do correct me. But as far as I know, all above-mentioned things are only recorded in Eddas and those, for me at least, should be taken with a pinch of salt.