I'm too scared... 😔

K so I'm quite young, (17 to be exact), but I know there are a lot of you who are older than me so I was hoping to get some good advice from someone older than me and who may have been in the same position. K so this year is my last year of school and I want it to be awesome (naturally). Here's the thing, I have liked the same guy for four years (that's ALL of highschool). He's kinda shy and so am I and I don't really get to talk to him much cause I chicken out. He's a great guy. He's cute, sweet, polite, and seriously perfect bf material for someone like me. Anyways, after highschool, idk if I'll ever see him again because I'll be working in the UK for a year (I'm from New Zealand) so I really want to get him to notice me and then see if he's interested. I really don't know what to do and Im not too keen on asking a friend to find out cause that's really childish. I need help on deciphering what the most adult, Mature, attractive (lol) way to see if he's interested. Idk if I make sense I'm just stressing my self out and I need some big sister advice. Thanks everyone!  Xx