We've been on our first date? See the texts he's sending me? Is he a good guy?

He doesn't seem "desperate" but he's a bit overeager to get to some kind of "guarantee" of your interest. If I were you, I'd gently avoid the question completely, or simply tell him what you said here - you "need more time" to understand your own feelings better. If he can't be patient with you, you would be well-advised to get out of it now.