Is he really into me?

Okay so there is this guy at my school and he told me he likes me and he checks me out at school. Also before we started flirting be would skip school and multiple days at school, But now he goes everyday. But I asked him out and i waited 3 days and he still didn't reply, So today at school i asked him to answer me. And he said "I really don't know" and "ask me some other time" Why would he say that if he likes me and he has told me he has. Plus at school today the teacher even made remarks like "Stop flirting you too" and "Tiffany don't miss pj's phone call tonight" But why would he say he don't know? And did i get rejected?