A Slippery Slope of Exploration

I've been casually dating this guy for a couple weeks now. We hang out and talk mostly, nothing serious yet but there's definitely potential. Last night we were just watching some videos together when one with a lot of close-up kissing scenes came on. I didn't realize it at first but before I knew it, my hand was tracing the outline of his crotch through his jeans. I wasn't expecting this to happen honestly. We've been so chill and laid back until now. It's weird for me since I usually try to be all about being in control and not showing too much vulnerability. But there was just something about the way he looked at me after that... He got up and grabbed a condom from his nightstand which was unexpected but kinda exciting. I mean, we ended up just watching more movies afterwards instead of anything serious happening right then. Just knowing I could though, if I wanted to. I've been thinking all day about how my body reacted so strongly despite me not really expecting or planning for it. Is this normal? Am I going to end up jumping into something before I'm ready?