Does 20 credit hours of school sound overwhelming?

I’m taking 20 credit hours 1 class will be online. I did it that way because it didn’t fit in to my school schedule…the classes overlapped. When I start school I’ll be working for my parents’ business about 30 hours a week but they can be flexible if I need to do homework and study.

What do you think? I mean personally is that over whelming for you if you have no job or a part time job?