I’m 33 and had never read a manga, and wasn't really interested in it. But I promised my huge manga geek little sister I’d go through a full series of her choice. Got a few days off, so Attack on Titan it is. Currently on vol. 21/34 and really enjoying it. Great characters and world-building, a bit like Game of Thrones. You got the usual Japanese themes of violence, sacrifice, destruction but those are well written. Storytelling pace is solid. Not a huge fan of the art, though it does seem like it gets more polished later on.