DD did exactly that--reapplied to CGA while in NROTC. She completely rewrote her essays with the benefit of at least a semester of college. My advice to her is the same I offer to you--take advantage of every opportunity in college and NROTC that's available to you, even if you don't think it's of immediate use. As an example, DD volunteered for a school project outside of her engineering major and threw herself into the task. Doing well on the task led to a paid teaching assistant position (as a freshman) and she was able to talk about that in her revamped essays.
She was also able to transfer virtually all or all of her freshman class credits to CGA (it helped that her major was virtually unchanged--Ocean Engineering to Naval Engineering). Regardless of your major if you go NROTC, try to take as close a class schedule as you can to that of a 4th class cadet at the academy. All cadets, regardless of major, are required to take a core of STEM courses.