You have elected that you want to change your age by changing the 23 but to what? You've got to think about the consequences of going too much younger or older, but also think about the advantage of doing it as well.
If you go too young then who knows how the people around you will treat you, but going to old how would that affect the relationships you have? Then being young would let you have a carefree time but again, it has its costs. You feel butterflies in your stomach as the writer part of your mind contemplates all the scenarios that could occur from whichever direction you decide to go.
Overall it then occurs to you, it doesn't really matter. I mean an app like this doesn't really do what it says it does, just have some fun. In the end you decide to change 23 to...