That would definitely help you in your aspirations. The field of nuclear engineering, be it with fission or fusion, is a highly complicated and advanced one drawing from all STEM fields, and requires a great expertise in them. Needless to say, a good deal of passion for the subject would also be desirable for long-term goals, although I see that you already have that.
What exact degree you should go for is really a matter of what type of job you want to do with the nuclear sciences. To actually build the reactors, you would need to major in general physics, mathematics, and focus on nuclear physics and engineering. To be involved with facility construction/design would require more of the same, with some additional training in architecture. A lot of reactors (especially these new experimental fusion ones due to their complexity) are run and controlled by a labyrinthine complex of computers - so seeking out a education as a programmer, AI-coder or computer architect would also pay off. Before you can even be involved with the highly technical cutting-edge research of fusion technology, you would no doubt be engaged in near-constant lab work etc, as you try to get a Masters or (ideally) a PhD in some nuclear-related STEM field.
Aside from funding and PR, there is not much a private citizen can do to directly contribute to fusion research. Your best bet would be to get a GOOD education in the sciences. I'm not trying to shot down your dream or anything, just giving you a realistic answer.
I'd say these links would give you a good overview of the education you need: