OMG Is It Normal To Spy On My Cousins?

So my cousins and I were hanging out yesterday at Aunt Karen's place. We found an old bin of baby dolls, and we all decided to have a little doll fashion show, I mean, it was totally innocent, right? But then, after they went inside for dinner, I couldn't help but peek into their room from the window while they were playing dress-up with the dolls again. It's not like I'm trying to be creepy or anything... I just wanted to see what fun costumes and outfits they'd come up with next! And honestly, it made me feel a little jealous because my cousins get to have all these fun pretend games and I feel like an adult with responsibilities now. Am I being the asshole for spying on them?