Well, I am currently living in Europe with no family in the US and going to HS, and I'm pretty sure I won't be able to go to college in the US (and get a student visa) as my parents are probably not gonna pay for the same quality education that I could get for a lot less money in the EU. But maybe when I got my B.sc., when I'm 24, I can get a Masters or something or start working in the US. So I'd expect to have about 8-10 years from going to the US at like 24 until the highest age limit of all branches which is I think 34 in the Navy when I get an age waiver(?).