It is very interesting to see who starts off absolutely sure they are going one direction and end up changing their ultimate destination entirely! One of the best parts about KP is the real-life Sea Year experience which gives the Mids a good look at the maritime life/career. That changes minds.
Roughly +/- 75% come into USMMA saying they are going to go to commission into an active duty service branch, and at the end, +/- 75% do NOT commission into an active duty service branch. Things change as they see all the opportunities afforded to them with a USMMA degree and USCG license. As a parent of a 2021, I've been fascinated with hearing all the stories and seeing Mids choose their paths.
Best advice to give your son/daughter is to keep an open mind. Golden opportunity to choose the right path for you!