Men and women aren’t separate species. If he’s asking this question, it probably means what it usually means: he wants the two of you to be in some sort of defined or “official” relationship. People who want to keep it casual don’t call the question because staying undefined helps them. They can always resort to lines like “we never said what we were” or “there’s nothing official going on here.”
Long story short, if he’s asking the question, he’s probably hoping that you’re going to say that the two of you are dating or that you want to be an “official” couple. If that’s what you want, go for it. And if it’s not, tell him that. Just tell him the truth and the rest will work itself out. You don’t want to be with someone who doesn’t want the same thing out of the relationship as you (whatever kind of relationship it is).
@Pachy I don’t agree that early use of “love” necessarily denotes immaturity. A lot depends on other factors. My first girlfriend used it right away, but it was clear from the casualness and tone that it was just how she differentiated romantic relationships from friendly ones. She hated the word “like” as a euphemism for attraction or romantic feelings. So she used “love” and was upfront about what the word meant to her (and what it didn’t mean). Hard to call that immature.