What do I do? I like this older guy. But I didn't know he was "older" until today...?

Yea I'd put you in your early 20's, you have that innocence of youth in your eyes, not that you're innocent just a sparkle the eyes give off, hard to really explain till you're older I guess LOL There's nothing wrong with dating someone that old, especially since you are 19. You're legal to do whatever you want and so is he. Twisted by some yes, but not illegal by any means. Very few of these relationships work, but when they do it's magic. The only thing that should deter you from liking someone is if they are mean and abusive, a good guy is hard to find at any age! Trust me I'm a guy and I know how hard it is to find decent men out there. Go for some lunch, some coffee, something small, dinner is too romantic and intimate for such an early meeting. Something small and simple like a lunch is perfect for talking and getting to know each other, and finding if you have anything in common, he lived in a different time so it may be hard to find mutual topics to discuss. Even then, the sparks may fly, so you really have nothing to lose by going out with him, if it doesn't work out, then cough it up to life experience, and if it does, well then all the better.