I’ll answer in order
1 it’s really cool, because it’s literally everything, every single thing is made of atoms and every other physics is what happens when they get together.
2 fission but when I was 12 I wanted to build a fusor ( got as far as designing one that should have achieved fusion)
3 propulsion/ applied also NTP stands for nuclear thermal propulsion, its what I’d most like to work on.
4 I always have loved science and I discovered it early on, I guess I just thought that it was really cool and made sense to me
5 I plan to attend Virginia tech for
Aerospace Engineering and get a BE and eventually I’d love to work with nuclear propulsion systems since I feel that they are the gateway to the planets.
As someone with a BS in AeroE, if your primary interest was in NTP, my recommendation would be majoring in Nuclear Engineering, with a minor or double major in Astrophysics. Even though I focused on the Astro side, almost half my workload was focused on things relating to airplanes that aren't terribly relevant to spaceflight.
Of course you could always just get a Masters or PHd in NucE after you get your BE.