You may be able to amend the birth certificate. Check this website for instructions:
http://www.dshs.state.tx.us/VS/reqproc/amendment.shtmAsk a similar question
I agree with Teri! It's the easiest way to start. Both parents would need to sign to amend the original birth certificate.
If they refuse, you would need to do a name change. It can be done but it costs $$ and takes awhile.Ask a similar question