I'm really scared, I'm 13 and wanna tell my best friend (who's a girl) that I'm bi/ I recently realized and have yet to tell her, I'm trying to work up the nerve but keep worrying what will happen?

Me and my bestie are both girls, but she has only ever had boyfriends i don't know what to do! I started realizing that I was bi/ this year because since I was 10 I hav been looking at girls boobs/butts, but I also like guys, I hav my first crush in a guy, not really huge though, I'm more into personality. But I'm really scared, what if she dosent wanna be friends any more or dosent wanna hav sleepovers? I wanna tell her now but I don't know how to introduce the subject. I wanna tell her over FaceTime cauz the only other times we get to talk are at school, but I'm really scared and hav never told Any 1. Once my mum asked me why I didn't like any guys and asked if I liked girls but I said no, that's when I was just realizing it about 7months ago. I'm really scared & don't know what to do, plz help!