Confusion

I'm in grade 10 and a guy in my class asked me out for lunch. I thought it was kind of weird because we've never actually spoken in class. At the time we just started snapchatting. I said yes anyways because he seemed like a nice guy. So we went out for lunch then around 3 or 4 days later we stopped talking all together. Not in class or on snapchat. So I waited a.few more days to see if he would talk to me. Idk why we aren't talking now. I snapchatted him and just said hey then I was gonna ask him. Did I do something wrong? This is just confusing for me