How does it work?

Has any of you joined the Navy or Air Force? My step dad cousin was talking to me about it. I'm in school for nursing, 3 semester away from getting my associates degree. She was telling me that I should join the Navy or Air force and work with them and keep going with my carreer, she told me a lot about it and I got really interested and now I considering join them. She told me that after I pasa their test they send me to the boot camp, and go from there. I stared a new job but she told me that I have to quit if I get in. Has anybody joined them? How does it really work? Do you still go to classes while in the training? Please any info will be appreciated . ❤️