When I Stole My Little Brother's Toys

So here’s the deal, I was always meant to be the big brother who looked out for my little bro. But there are times when it’s hard being the oldest, you know? Like last week, when he came home with a new set of Legos and started building this epic spaceship right in front of me while I had no cool toys left to play with. It was just sitting there, and seeing him so engrossed made something in my brain click. 'You deserve some fun too,' it said. So, when he went for a snack break, I couldn’t resist, I snuck those Legos right out of his room and started building myself. And you know what? It felt surprisingly good to have the latest set all to myself, even if only for an hour or two before guilt hit me hard. I put them back exactly as I found them but now, every time he gets excited about his toys, a part of me feels like it’s my own little victory. But here’s where I’m stuck: is this normal sibling rivalry? Am I just not growing up fast enough to let him have his things without getting jealous? Or am I just plain old selfish? Anyone else ever do something similar and regret it later? Is that what being the older one is all about, or was this more of a momentary lapse in judgment? Any advice on how to move past this?