Annoyed at my best friend?

I recently watched a movie that just came out and I love it so much that I've already watched it 3 times, my laptop background is of the movie and I've been looking for posters everywhere so I can have it up on my wall. So the other day, I watched it with my best friend, and now she loves it too. I know this is really really stupid, but the way she goes on about the movie really annoys me. We were mucking around in class (before she even saw the movie, but I had) and we were listing our celebrity 'husbands' and the main guy from the movie was in my list, meaning if hypothetically, we met him, I would already have 'dibs' on him. Now since shes seen the movie, shes been telling me he's hers. And now her desktop background i of him, whereas mine is of all the main characters. I feel really annoyed that shes like stolen him from me or something. And trust me, before you tell me to grow up, I know that. Don't you think that I feel stupid about feeling annoyed about something that doesn't even matter. I'm 16 years old. I honestly feel like the meanest, stupidest friend and person right now, so don't even bother telling me. But how can I stop feeling like this? He's just a celebrity that a lot of teenage girls drool over, so why do I feel annoyed that she's got him as her background, and she's constantly telling me they're gonna get married, and every minute shes like, Oh my God he's so hot. I feel very stupid and childish, but I can't help it.