Get over an older man?

I have a thing for an older guy, he's in his mid twenties and I am between 15 and 18. I understand that the idea of us together Is totally out of question, but I cannot get over him and I really want to. We talk a lot as friends and I am 99.9% there is no attraction on his side, but nothing I tell myself will help me get over him. What do I do?

its just a crush,get over it