Enough for what?
I am huge advocate for getting an education for education's sake.
There is no degree requirement to be a stage manager, but, as a human being, you might want to continue your education.
I try to strongly discourage the concept of going to college for a specific job. It puts tremendous pressure on people to make up their minds what they are going to do for the rest of their life at the age of 17, which makes A LOT of people miserable in their 20's as they TRY to make the career they went to college work for them.
Hell, at 17 (even at 20), I had no idea I wanted to be a stage manager. I had no idea that was going to do theatre - but I cherish my education because it made me an all around more rounded person. (I know this sounds a little pollyannaish - but the my entire random, odd and long education experience makes me part of who I am today.)
But, hell, if you are working at the level you want to be working at and you feel you are marketable at the level you want to be working now, and ready to be the business of one - then go for it.