Did he really ask me out?

I was ping notes with the guy I've liked for a really long time. About a month ago he told me over Skype chat that he liked him and I told him too, but ever since then nothing happened until today. He suddenly randomly wrote on the note "What would you say if I asked you out." I just replied, "umm idk" then we were in our homeroom getting money for break and he told me I was "mean" haha and then he kind of jogged out of the cl where my best friend was waiting for me and then when i came out a minute later she told me when he came out he told her he liked me and then he ran to catch up with his friends down the hall. can somebody tell me what this all means? i feel really bad and i regret not just telling him i'd say yes in the first place. helpp!!! thanks