sticky situation

so there's this guy who was in 2 of my classes in 7th grade ( i'm going into 10th this year) and in december someone gave him my number and he said he has had a crush on me since 7th grade and i was just like ok that's weird. then he got my snapchat somehow and we've been snapping back and forth. he just asked me to go to a movie with him and i said sure but i'm out of town right now. i really don't like him and haven't actually talked to him since 7th grade and i don't want to be mean and not go to the movie. and i can't just keep making up excuses. please help if you have any suggestions.