Two things together that will make West Point STEM classes EASY:
1. The desire to learn
2. Time management
This is coming from someone who had below a 3.5 GPA in high school (a very terrible high school at that, took minimal AP classes) and who took many years off in the Army before returning to academics. I've never had a 4.0 GPA semester in my life.
I am a rising Firstie now, am in disputably the toughest major at West Point (*hint* its one of the engineerings), and have over a 3.5 GPA.
How did I do it? The desire to learn and time management. The desire to learn will ensure you stay awake in class and listen to the professor. By merely paying attention in class, asking questions when you don't understand a concept, and then grinding your ass off the night before a WPR, you will receive AT LEAST a B in any STEM class. To get an A, you need to be naturally strong in STEM courses OR you need to use time management and the desire to learn together to read the assigned pages before each lecture (probably less than 10% of cadets actually do this). I didn't know what a derivative was until Yuk year and I received an A in Calc 1 and an A+ in Calc 2. It was a combination of the those two components that enabled me to do this. This desire allowed me to internalize many important concepts which enhanced my performance greatly.
Take it for what its worth.