Am I over exaggerating

Okay y’all I’m trying to see if I’m over reacting or not. Soooo okay , I met my boyfriend about 2 years ago when I was a junior. We had drivers Ed class together and him and my cousin used to be like real close (I never knew that until I seen them together a lot) but anyways me and him started talking and texting and then we both started liking eachother . Neither one of us thought we would get this deep into it. (We are currently in a happy two year relationship. But the thing is a few months ago I had my cousin phone and seen messages of her and some other female talking about him. Saying she liked him and how she’s not gonna be the second option etc. and then I went through their snap messages and she was talking about she had a dream about them having sex (it was before me and him started having feelings. But I still feel some type of way about it . But anyways I had asked her about it and both of them said they didnt like eachother. This is where the trust issues comes , I have trust issues because I honestly don’t trust her around my boyfriend at all . Am I over exaggerating or not . I love my boyfriend and he really want me to trust him . I trust him a lot it’s just the other people in my life I don’t trust around him