Whilst there seems to be no shortage of talented people looking for non-profit jobs, there is always a shortage of money, and my donating would be unlikely decrease anyone else's donations. So, I feel this is the more effective option.

That's probably a safe assumption to make in most charitable fields, but not in existential risk reduction. For example, there are not enough qualified candidates for the position of FAI programmer, or to lead the project that Nesov recently suggested.

Compare the following hypothetical scenarios:

1. There are qualified candidates for an FAI team ready to go, just waiting for sufficient financial resources.
2. SIAI gets a $1 billion donation tomorrow, but has nobody to hire.

Which is easier to remedy? I suspect 1, because people like Peter Thiel can probably be persuaded to donate significantly more money if only they thought FAI had a more realistic chance of success.

Come to think of it, your main comparative advantage is that you're young. There are plenty of people in the world who can be donors, but not too many who have realized, at an age like yours, that they should think strategically about how to change the future. Having such a realization can be compared to winning the lottery. It may be that you should aim to be a donor after all, but to do so without thinking very carefully about whether you can specialize in an area that the future will really need, would be to throw away the winning ticket instead of cashing it.

(ETA: The above assumes that the main thing that a young person can do that others can't (or can't do as well) is to become a specialist that the future will need badly. But perhaps there are others?)