Do I actually even like him?
Dating is precisely for figuring this out. I think everyone gets a bit nervous for a first date, but you don't need to put so much pressure on yourself. If it ends up feeling a bit awkward, you don't have much to talk about, or you just don't really click, then you don't see each other again. It won't be a disaster if that happens.
As for what to talk about, what kind of stuff have you been chatting about already? Presumably you have some common interests you could bring up? A good trick to keep the conversation flowing is when your date mentions something about themselves, respond with a question rather than a statement. For example, if he says he went on holiday to Spain last summer, instead of responding with "that sounds nice", respond with "what was your favourite part of the trip?", or "what did you like most about Spain?". If he's talking about a hobby, asks him what he likes about said hobby. This may sound obvious but I'm quite shy and socially anxious too and this has helped me a lot with conversation!
Also, when I'm feeling really nervous about something, I try to tell myself instead that it's excitement rather than nerves. It's basically the same feeling, but if you keep telling yourself you're dreading it then you'll feel much more anxious than if you tell yourself you're excited for it.
Good luck and enjoy yourself!