Changing a child's surname

[jntasm]

I currently live in the state of Texas and my son was born in Washington DC. He is 6 years old and the people from the vital records office contact me today to say that I could not change his name using the documents they gave me. That I would need to get married or petition the courts. What courts would I have to petition, the ones in Texas or the ones in Washington DC? She stated that since my child was over 6 years old that I could not change his name to his fathers, even though his father filled out his forms as well. I never knew there was an age limit to changing children's names, when they send you the forms. Thanks for any help with this matter.

 

[seniorjudge]

Where is the father?