Make sure that you always change your birthday, even if it’s a wrong one, to 13 years of age or older to be able to change it at a later date. How to change your age on Roblox account (PC desktop)?

Steps for altering your avatar’s appearance in every Roblox experience, from adding and removing items to changing your skin ...

ROBLOX allows you to change this username, as well as your Display Name. It’s important to note that there are different rules and applications of both Usernames and Display Names.