I (15F) really love this girl that's graduating (17F) I know it won't last but I'm conflicted on what to do to lessen the blow of her leaving

Hi, Im P (15F) the girl I like is M (17F) I'm currently a sophmore but we've been on and off since my freshman year. Actually since BEFORE my freshman year we started talking when I was 14 going to hs and she was 16(sophmore going to junior year). She was what made me realize I was gay in the first place. We've had our problems and been on and off for about a year a little over. She's stayed through so much. Now shes graduating and I don't know what to do. Part of me wants to self sabotage things so I'll be less hurt when she goes. Part of me knows I should stay until the end but I just would do anything to make this hurt less.