What these guys said. From what i can see it seems like he's acted too slow and so you didn't really consider him before.
Try imagining if someone else - who you haven't relegated to "just friends" yet but who looks and acts the same way - asked you out? Would you go for it? If yes, then same answer here. Just don't restrict you're view of him to a friend when you go, or you're just stringing him along.