Is this immature? What should I do about my Facebook URL name?

[manne]

So I want to change my Facebook url, but I dont think I can. I made my facebook when I was 15 and I called my url-Cookiemonster23. Now I am 23 years old and I am working and have a job, but when I add my coworkers I feel so embarrassed because my url makes me sound like a child. Everyone else uses there real name.

[T]

Shepherd thy people with thy staff, the flock of thy inheritance, who dwell alone in a forest in the midst of a garden land; let them feed in Bashan and Gilead as in the days of old. As in the days when you came out of the land of Egypt I will show them marvelous things. Who is a God like thee, pardoning iniquity and passing over transgression for the remnant of his inheritance? He does not retain his anger for ever because he delights in steadfast love. He will again have compassion upon us, he will tread our iniquities under foot. Thou wilt cast all our sins into the depths of the sea. Thou wilt show faithfulness to Jacob and steadfast love to Abraham, as thou hast sworn to our fathers from the days of old.