I’m a 15 year old boy that’s attracted to an 18 year old girl.

Hi, r/dating_advice! So, the title should explain itself, but, in more detail, I'm a bit of a nerdy, shy high school freshman, and I have a crush who makes me so happy to be alive! I really admire her ethics and social awareness, and she's just a very pleasant person all around. Only problem is, she's 18 and graduating this week. Should I even bother telling her how I feel? Especially given how we'd be unable to physically interact, and how it'd be unfair to expect her to return my feelings anyway, I'm really torn. Please tell me what you think (throwaway because I'd forgotten my old password).