my friend is acting like a whore

hey, so recently my closest friend is acting like such a whore. we’ve been friends for a little over a year and recently she isn’t acting the same as she usually does.. we haven’t hung out in like 3 months because she keeps blowing me off to go to other guy’s houses. she already sucked a guy’s dick and she only just turned 13! i’m a year older than her and i never even had a boyfriend before.. last year she kept switching between the same two guys, she’d date one of them for a few days and then date the other one, and that was an ongoing cycle for a while. she went to a guy’s house and he posted a video of her on snapchat swinging around on a pole and yelled “stripper!” she just laughed and acted like she liked it :/ and like i said, she’s only 13 and we’re only in 8th grade!! i just tried to talk to her about it and she got sooo pissed and defensive and i’m afraid of losing her :( any suggestions??