I'm 22 years old, but I feel like I'm 13-15 years old… I don't look like I'm 22. So in terms of clothes (like to wear boys clothes for teenagers) (with e.g. Fortnite or something on it)
What does normal mean, everyone is a little crazy in their own way ;-)
But I think you are not fully mature in your head, at some point it will not be any different…
Then you probably stopped in your development. At that age, some start up companies and don't feel like 13.
If you think you feel very young, you think you are young but you are not. It is completely normal what you wear. Whether Fortnite clothes or something else, I could only say you feel comfortable in your own style. No matter what others say, it just feels cool.