In terms of working hours, I would say stick to 6-8 hours for your first semester. It’s going to be a huge adjustment and you don’t want to have to dig yourself out due to taking on too much.
You’ll get a syllabus, often before the first day of class or on that day. You must go through it carefully and enter the due dates in your phone or synch’ed calendar , with a reminder 1 week before, 2 days before, 1d before. For every single one. Then look at the overview week by week and start planning backwards.
When there’s a reference on a date, it means it’s due then - the reading must be done before class, the p-set must be completed before class, etc. “Reading done” means you highlighted bits but, most importantly, wrote down important notes, concepts, etc in your notebook* and added questions on a special “reserved” section of the page as you read. This way you can refer to it if the answer was given in the lecture, but if it wasn’t, you can ask during office hours.
Textbooks: do NOT buy new – rent them or buy “old” books, or, even better, use the “reserve” at the library(free). if you don’t have any money (they’re costly), ask a professors whether they might have an old copy you could use till you have enough money to buy a 2nd hand copy.
Office hours: professors LOVE to see students during office hours, especially during the beginning of the semester. It’s their opportunity to meet you one-on-one. (One week before the midterm is way to late, sth many freshmen learn the hard way.) So, come with your notes and questions. They’ll love answering them. If you didn’t understand a solution, show your work and ask where you went wrong. If everything was crystal clear, let them know, they’ll love the feedback on their lecture. If something interested you, ask for a book you could check out about it, or an article you could read, or a video you could watch.
Professors, unlike teachers, don’t hang out in their classroom. They don’t even have a classroom. They go in and out of the classroom they’ve been assigned, and after their lecture or seminar they leave because someone else comes in, so there’s no “chit chat” the way it is in HS. What they do have is an office, where they hang out, prep, read, etc. So, if you want to see your professors, go to office hours.
Book tutors during your first week, before others have the same idea. 
Make sure to reserve in advance, a few days before each test or before any paper due date. Tutors are often the difference between a B and an A (and, yes, students who want A’s use tutors).
Pace:
in HS, an AP class will have about 40 weeks of school, 5 hours a week, per subject. So, about 200 hours to cover, say, Calc AB.
In College, the equivalent of Calc AB is covered in 13-14 weeks, 4 hours a week. Do the math and imagine how much work you must do outside of class, with tutors, through office hours.
Now, multiply this by 4…
I’m not sure whether you CAN start ChemE in the Spring, since the core ChemE class is only offered in the Fall. Can you check with the department there?
If I read properly, in the Fall you’d take Math 16100, Chem 2000, Phys 17200, ENG 13100, and, I assume Freshman Composition – and all save for Freshman Comp would be pre-reqs … how does it work @momofboiler1 ?
