Just a Night Out?

So last night, I met up with an old friend I hadn't seen in ages. We hit it off and ended up at my place. Next thing you know, we were laughing about old times, then things got cozy really quick. It was fun but... not exactly what I expected to happen on a casual date. Is this normal? Do people usually have such unexpected turns with someone they've just started seeing casually? What do you all think?