trying to go for international schooling- help!!

im just gonna introduce myself since i rarely ever post, so this can kind of be my first real post or whatever. im a 15 year old sophomore in a US public school, and i just need some advice. im looking into going to school at a scottish university, since i desperately want to get out of the US. i want to go there for my undergrad and masters, and i have a few schools in mind. i want to get out of the US ASAP. however, there are two main issues- i don't know if my grades are good enough, and money. right now, my unweighted gpa is around a 3.5, and my weighted is a 4.3. i take a lot of rigorous classes (right now i'm in 2 AP classes and all honours), and i'm trying my best to look into getting scholarships. i know that financial aid is possible in small quantities for scotland, but i just don't know how i am going to get there. my family is not wealthy, and i would be self funded. i know i'm batting against all odds, but i really want to pursue a career there. my main study is computer engineering (hardware) and i would probably minor in some music program. any help is much appreciated, thanks!