It's not about age, it's about time dedicated to that activity. People around 15-40 (Answer for your question) years have already developed/are developing their bodies, so it'll be their primr at anything they choose to do, but, the amount of training you put on it (6 hours a day of that specific activity for example) is what will separate you from other that do it casually. You in your 20's can't play a genre of game for shit, but your grandma or younger sibling can bc they invest their time on it. Same thing with sports, music, social interactions, everything in life.
Want to play like a pro? Train like one.