Deion Sanders -- First Day of School is Priiiiimetime (VIDEO)

Deion Sanders makes you want to go back to school ... now!

Prime got his 3 youngest kids ready for the first day back to school with Tupac blaring in his mansion -- and an inspirational speech.

It's unclear if the enthusiasm worked on his kids ... they're noticeably absent from the vid. Still, if your dad was this pumped for school ... you might have actually passed advanced calc.