My son also turned from a boy to a man between the time we dropped him off Ft. Detrick for his trip to Lakes and when we saw him a couple of months later at graduation. It is interesting to observe how he is very professional and focused while in uniform but whenever he comes home on the weekend and gets back with his friends, he reverts to old behavior! I have to remind myself that he's still only 20.
It appears all of them do this! When my son stepped off the plane, he was a true sailor standing tall and proud. He spoke like a grown up. The next day when he was in his regular clothes and with his friends, he was like the kid he was back in November. The next day when he had to put on the uniform again, it was like watching a movie where they morph one person into another! As my son said, this was his only chance to be "himself" and while he was on leave, he was going to take advantage of it. He pointed this out until the day he left. :-)