Happym19, crazybrit was assuming that your screen name was based on your age, and that you wanted to change it because you had a birthday.
In case you want a new screen name, you can simply open a new account with a different email address. As long as you don’t use both to appear as two different posters, the mods should be fine with it (although you never know if one mod wasn’t paying attention when this rule was taught in mod school 😉 ).