I'm currently taking the minimum 12 units for a full time student at my freshmen year at community college & even thought I'm barely getting by. I know that if I didn't procrastinate so much, I could excel & possibly add 3 more units. I think if you were a pretty self disciplined, organized & responsible student in high school then you might be able to manage. I don't why you would want to overwhelm yourself so much as a freshmen, but I've heard of a couple of older students doing 18+ units & being successful. I just wouldn't add another math or science as that could turn you courseload from manageable to impossible. Time management is key.
Sent from my ADR6300 using CC