Daiki Sato was only 14 when he met Levi, but even as a kid and the one time he met him, he looked up to him and admired him. then he was sent to train and go through the survey corp camp. 4 years later, At age 18 he joins the scouts, and is like a big brother to the 104th cadets. and only when erens titan is revealed does he meet Levi again. but he wasnt a child anymore, he was an adult and fully grown.