Should I worry about their friendship?

So there is this girl that I dont really like. My boyfriend however is friends with her and he knows it bugs me but he thinks thats dumb because I have other guy firneds too. He swears that I have nothing to worry about and I have no reason to not trust him on that. But there is something about this girl. I dont get mad about any other girl but this one just annoys me. of course shes older than me to make matters worse. So what shoudl I do? I have talked to him already and he thinkns I worry to much because I worry about everything but still. Should I worry?

You're fourteen and he's nineteen. That's the one thing you need to worry about.