How can I ensure AC in Navy

(I asked this in a air force thread and they said I would be better of enlisting Navy, I've been having trouble deciding between the 2) I know this may not be the most ethically correct way to fight for the country but I am trying to find the balance of what is best for my life. I am 17 set to graduate in march I am in great shape 6'2 190lbs 225 bench 370lb squat I have 20/17 vision and great hearing. I know the Air Force doesn't actually gaurentee jobs but I am doing Air Force for ATC and I know thats backwards but it's the truth. I wont do any other jobs. I havw heard If I can just pass the extra testing ATC go through I will basically be gaurenteed because of how rare it is that apicants pass. Is It also possible I wait in delayed entry so I can get the job? Can anyone point me in some direction all is appreciated this is my honest thought process and I am sorry if I offended anyone I just don't want to be stuck doing a job for 5 years when I already know what I want to do.