Is there a way I can change my branch of the military if im all ready dep in a different branch?

I am currently in high school and dep into the US Army, but i always wanted to join the Air Force. I took the asvab and ped for any branch i wanted to go in to but at the time the Air Force recruiter wasn't in but the army was and they invited me over. But I have been thinking about switching to the Air Force because there really isn't anything in the Army that i want to do. So is it possible for me to switch?