He joined the Marines and I don't recognize him

My cousin joined the marines and he doesn't even look like the same person. You would think joining the marines would make you bulk up in muscle but no he's so skinny I don't recognize him at all, he's just finished training and honestly I'm terrified to see him in person and talk to him, the pictures and videos he's in he just looks completely terrifying to me even though he's much smaller than he used to be. Just the look in his face is so blank it shakes me up. Is that like normal do any of you have family in the marines and felt like this at first? I don't know maybe when I finally see him in person and talk to him I'll feel differently.