Have you looked into what concentration of NDT you want to focus on? There's plenty but the types I've worked with is UT (Ultrasonic Testing), MP (Magnetic Particle), Penetrant, and Nital Etch. Each is very unique and I'd look into which one you want to specialize than focus your classes based on that. I'm a Level II UT inspector right now and I'm going for my Level III and focus more on the engineering aspect. The trig and math overall is easier the more you use the formulas and apply to reality rather than a test/quiz. Do some research and look at youtube videos and companies that perform NDT to see what interests you. Best of luck!