Although OP clears one big hurdle of getting accepted for ROTC (U.S. citizenship), the fact that OP has lived overseas for 12+ years and the parents are not U.S. citizens makes it very unlikely that an ROTC scholarship is in the cards (security clearance issues). Anyway, it sounds like OP has not even started an application process, so my guess is it’s very late, maybe too late, to get started.