My gf chills with other guys should I be worried?(explanation included)?

Ok so me and this girl have liked each other for like a month now..I've went and seen her twice we both are 15 we made out a lot and cuddled. But she's going to a farm wiith like 3 guys..and this 1 guy always chills with her..and her profile pics iis of him and her..I dono should I be worried I talked to her and she keeps telliing me that I'm the one she wants no other guy..so anybody got some advice am I just being jelous I've got a lot of anger in me about this and I wanna punch my wall till my nuckles break..so anyone advce please should I let it go or what?? I don't chill wiith other girls so yea thanks in advance