Hello boyos

I need some guidance.

I’m an aircraft mechanic, formerly worked for SpaceX as a technician.

I demonstrated myself at my last job, creating processes and working with the engineers directly to solve a number of problems. I always told myself that if I lost the technician job, I would try and go back to school to become an engineer.

I work for a school now, who pays for my education while allowing me to continue my technical work as an aircraft mechanic.

I’ve been taking classes towards my Aerospace Engineering degree (my bosses guffawed at this, since it’s considered one of the hardest tracks at the school I work for), and I have a 4.0 GPA.

I am just completing my calculus courses (redoing them to get my skills back)... what I want to know is, what are the biggest pitfalls and hardest courses, generally, in the Engineering track? I want to know how I can best prepare for some of the harder material. I am on a good track now, but I am mostly interested in three things:

a) getting the most relevant engineering skills (a lot of the engineers I worked with were... idealistic?)
b) maintaining a 4.0 or staying close to it
c) finishing my degree in a relatively short timeframe (the school pays for 18 credits a year, so at this pace I am about 3.5 years off)

Thanks for your help folks. I will post my degree program when I can find it.