he’s older 😬

I have been sorta talking to a guy, but he’s a senior this year and imma be a sophomore this year. I don’t know if my mom will be okay if I dated him, but he’s super sweet and nice to me! I’ve told her about him and that we wanted to hang out, but I haven’t told her he’s 17 and i’m 15. I know everyone says age doesn’t matter, but I feel like to most people in high school it does, i don’t know! Can some people give me some advice on what to do or if I should end it with him or tell my mom or what?!?! thanks!!!!