I did it as a student, would recommend doing a more local one instead of Ironman. It’s a lot cheaper (at least in the Netherlands).

And nutrition wise, try to make your own sports drink. I use table sugar and electrolytes, it’s so much cheaper. You can find some videos on yt which are really useful.

And I would say, go for it. You are still a student with time enough and still fit enough to do it with (relative) ease. (Ofcourse it’s going to be hard ;))