My bf wont take me to prom

He said he’s going to take another girl and I’m just a year younger than him and he’s a senior, I don’t plan on going next year, but he said he’s going to take one of his “girl friends” and he’s gonna hang out with his friends 🤔 I’ve honestly been bugging him this whole time to take me but he says I don’t know his friends therefore he shouldn’t take me, I’ve been crying (I’m still a big baby) and sometimes begging him to take me but still he says no, he says if I keep asking he won’t go at all.

And my best friend said he would take me but I really don’t wanna go with anyone else because I’ve been in a 6 month relationship with this person and this has been my longest relationship. I really don’t know what to do at this point I really do want him to go but then I wanna go with him. Any advice

P.S. I really wanted to get this off my chest