pls help, fam

so i had a crush on this girl and this girl also likes me. so it's mutual but we aint dating. just mutual relationship. i know that she likes me, and she knows that i like him.

the girl and i became friends, we hang a lot and pretty much know a lot abt each other. but then, i realized i was gay (bi) and i like this senior guy and the senior guy also likes me. we're dating now (secretly)

the thing is, the girl still thinks that i like her. idk how to tell her that i dont like her anymore and that im gay without hurting her. pls help.