Well...
It's good for a first. But... It's not in sync. What you should focus on is not haveing the syncing down yet, but actually haveing some more frames. I mean it's just picture by picture with some voices. Work on having them move. Everything else like th background (Bus) was pretty good. The characters were also drawn pretty well. The problem is, is that you need to put some more time and effort in this.
Overall I think it's ok for a first. But spend more time with your flash. Get the syncing down, maybe put mood in the voices. Make it seem like the are really talking to each other. LIke an acutal conversation. (I'm not saying you don't have that down.)
Long review short, take time in your submissions.