SHOULD I MSG THIS GUY ON FB OR NOT? IF YES WHAT SHOULD I SAY!!! HES LEAVING SCHOOL IN 7 DAYS!!!?ill answer urs?

[677]

Ok so im 17 yo girl, very shy around people i dont know, socially awkward sometimes.I have zero experience with guys. There is this one guy who I find cute for almost two years now, even though I dont know him and he doesnt know me. Hes graduating in less than two weeks, and ill prolly never see him again. I dont have any classes with him, i do seldom see him in hallways. I tried adding him on fb in December (stalkerish i know) he didnt accept, though i think he ignored it then i msged him saying hey. it never showed that the msg was seen by him, i think it went to his other inbox. Anyways i wanna do sth before its too late, i dont know if he has a gf :/ Will it be weird if i msg him on fb saying that i know hes leaving sooon, and that i just wanted to say hes cute? Right now we got 2 mutal friends on fb, so im scared if i send him this msg he will get the old one from December, and hell think im a creep or should i not worry since i will never see him again, so i might as well embarrasse myself?

ALSO If so far ( almost 2 years) I never did anything on the matter, I'll prolly be scared and now. So would it be betteter to try smiling at him in the hall or send a msg? When should I send the msg cos i know that if i see him in the hall ill feel embarassed the next day! What if he has a gf?? Am i gonna come off as a creep when he sees the old msg from the December? Will this msg now go to his real inbox? Should I add him again and then msg him?
So many thoughts running through my head!! Am i overthinking this? heeelllpppppppppppppppppp
Please any advice on this matter??