I second starting low and working your way up when you find out if you can handle it. I started out at about 20-25 and gradually went to 30 and now I average 39 while in school, but it took me awhile to find a groove that I was comfortable with. We have lots of hs/ college students that only do weekends or about 15 hrs, so nothing wrong with whatever you do. You do you, but school first.