Insecure from billie.

Me and my now gf, had been best friends before we got together, we knew we liked each other and stuff, and we always spoke of a relationship but knew it wasn't a good time until a month ago, now we are together, and we are a pretty jealous couple, with lots of rules and boundaries. This is where it starts sounding a bit crazy, she loves Billie Eilish, and I am all for that, but then I see myself getting obsessed with Billie, and going crazy because I compare every little thing about her with me. I never do this in any of my relationships, so I don't know what's happening. My girlfriend and I also had this convo about how different her type is from what I am, and I am starting to feel insecure, because my girl still goes crazy about Billie in Infront of me. IS IT OKAY TO FEEL LIKE THIS?