Is it possible to have a serious relationship after on the first date?

First off, I really hope y'all don't judge me. I went on a first date with a man, and we ended up having . I've never done that before. I was just so attracted to him and the moment felt right. My question is-did I completely blow any chance of turning this into a serious relationship? We talked on the phone/texted many times since, and plan on meeting again soon. He is 30, I am 23. So I guess guys around that age-would you think of me as just a fwb type if a girl slept with you on the first date?