How should i ask him to prom?

I need a date for prom and its in may but my friends and i want to deposit for the limo early. I was thinking of asking my friend who i haven't talked to in a while, and i was scared he would feel weird if i asked him out of the blue like that, but today he walked up behind me and gave me a hug and was like "hey it's been forever how you been?" and we kind of just picked up where we left off as friends, and he kept hugging me, so i said "i have a business proposition for you" and he put his arm around me and asked what it was and i told him i'd tell him later but now i'm scared he's not going to want to go with me and i'm going to look dumb because i'm a senior and he's a junior. what should i do?