I would suggest you use the word attractive instead of young. To look attractive, it is important that you feel good with who you are, and that includes not only your age, but every one of your external characteristics. There are things that you can do to look more attractive, but if you don't accept yourself and the way you look radically, you will be engaging in a divisive and painful thinking process. Since what you're aiming for is external recognition, know that people will always see the lack of confidence in you, and that's one of the most unattractive things.

https://www.youtube.com/watch?v=x1dO0cdXMig