Just met a guy.. now hes head over heels?

me and this guy mark met eachother through myspace becaus we go to the same school and our best friend angie told us we are perfect for eachother. so we met, and even before we met he was talking to me like he liked me soo much. well after we met he fell head over heals for me. is he just desperate or does he really like me? is it possible to fall for someone in a week of really knowimg them? we talked before but now we really know eachother. thanks. if it helps were sophomores in high school.