Are these girl just jealous?

well I'm a girl thats 15 and i have experience with these things. Girls can be really nasty and cruel. It could definitely be they are jealous you're happy and found better friends than them. The best advice i can give you is to not let it bother you when they talk about you. If you hear them say something just laugh it off and be like thats a good one you guys! They will get bored because you wont be getting upset and they'll eventually stop, just hang in there :]