Sora is approximately 15 to 16 years old during the events of Kingdom Hearts 3. He was 14 in the original Kingdom Hearts game, 15 in Kingdom Hearts 2 and Dream Drop Distance, and Kingdom Hearts 3 takes place shortly after Dream Drop Distance, so he is believed to be around 16 years old in KH3. Some sources suggest he could be as old as 17, but the general consensus is that he is about 16 during KH3, given the short time gap between the games