I've noticed that age in these mediums often carries deeper meaning than just a number. In 'Attack on Titan', Eren Yeager starts at 15, embodying the fiery recklessness of youth, while in 'Monster', Dr. Tenma's mid-30s age reflects his world-weary wisdom. The beauty lies in how these ages shape their journeys - Eren's teenage rage fuels his transformation, while Tenma's maturity anchors his moral compass.
Series like 'My Hero Academia' brilliantly use school settings to explore coming-of-age themes, where 15-16 isn't just about puberty but about finding one's place in a superpowered society. Contrast this with 'Ghost in the Shell', where Major Kusanagi's physical age becomes irrelevant in her cybernetic body, prompting existential questions. What fascinates me is how Japanese creators weave age into character arcs - it's never just biological but represents different stages of philosophical and emotional development.