My two cents...
Going to college and trying to work is fraught with a lot of pain. You simply cannot balance the two. I know this from experience.
I went to a local college to study physics. Compared to neighboring schools my highschool was behind the times. Our most advanced math course was Precalculus. It was a great course taught by a master teacher but it wasn't Calculus.
Over the summer, I learned Differential Calculus everything except the limit proofs. To me they were an unnecessary inconvenience. Fortunately, my college staggered the courses you needed to take to ensure that you would have both parts of Calculus under your belt by the time you started Introductory College Physics.
But I was working 20 hrs a week and I was in a hurry to learn more physics so I tested out of Differential Calculus. The prof was kind enough to approve after a brief test and a question on the meaning of the epsilon-delta limit proofs. That was the gotcha, I got it wrong and had to visit with him a couple of times explaining it in my own words. Finally in exasperation, I recited the book definition and he said you know I think you got it and smiled.
I thought I was pretty smart jumping ahead like that into meatier courses. I didn't care much about GPA or grades just learning. In hindsight, it would have been an easy A, and I let it pass me by.
During the first two years, I was able to glide through the important classes related to physics and math, but I was not too fond of chemistry for its afternoon 4-hour lab work. I was a commuter and tried to get all my classes in the morning so I could get the bus home in the afternoon, do some homework, and then go to work at the local Big-N department store. Big-N was a competitor to Kmart and very much like it, except we didn't have the blue light specials.
I even managed to take a few extra classes, which the college allowed without additional cost. Our college used a trimester system, with 10 weeks per trimester and three courses worth 3 and 1/3 credit hours each. Learning was very compressed. I knew of one student who doubled up taking six courses per trimester and effectively graduated with a four-year degree in two years while only paying for two years of college.
The third year, courses and homework started to get really tough and I had trouble keeping up. Each year of college is like 3 years of high school and if you don't stay on top of things or have the time to do so you will falter and fail.
My classical mechanics class (book Classical Dynamics by Marion) was taught on Mondays and Fridays. On Monday, we were given our homework for the week to be due the following Monday. I planned to wait until the weekend since I had no free time during the week which in hindsight was not a good plan.
In those days, we had no internet, only the college library, but being a commuter who worked, I had little time to go there and relied on my ability to get through the work. It always took me longer looking at whatever books I had to piece together an answer.
What made matters worse was that the Professor said, "Well, since you all are almost finished with Monday's work, here are a few more problems to be due on Monday, too." I was floored. I did my best, but I always managed to hand in my homework a few days late. The professor would tell me, "Your homework is good, its organized with clarity of thought but since it's late, I have to dock you a grade."
This pattern continued until I graduated with a low B average.
When my younger brother, who was 10 years younger than me, went to college, I told my parents that he shouldn't work because it would affect his grades. He didn't, and eventually, he got his PhD in physics. In contrast, I have a MS in Comp Sci and somehow I felt I failed in my mission. However, later while working full time managed to accrue almost enough graduate credits for an MS in Physics too.
My work allowed me to pay off my college loans six months after I graduated, but it impeded me from getting a higher academic degree like my brother did.
Please consider this story as relevant to your plan:
- working 20 hrs is too much
- no time to study / no time to play
- college gets tougher each year/people hit brick walls in their junior year
- don't skip courses you can do easily they will help your GPA
- don't work if you don't have to / it might give you 10 hours per week free time