Am i being jealousy for nothing?

I have been dating a new guy for a few weeks now. He is awesome. His friends, however, are almost all girls. Not just girls, really cute, skinny perky girls. I just met a bunch of them at dinner. He introduced me as his gf and all but he was still flirty with them. The girls are constantly making ual jokes and being flirty as well. I know they are just his friends but its weird for me to think my bf is constantly hanging out with beautiful, ual girls. Am i being stupid?