Ask a Lawyer and Get Answers to Your Legal Questions
You cannot change your birth certificate, but you can file an amendment. To do this, contact the County register for the county in which you were born and ask them for an application to file an amendment to birth certificate (many have these forms online).
You should be able to do this entirely by US Mail. Contact the county where you were born and ask for the packet.
(You said that you already changed your name - that is the only part where a personal appearance is required).
You can pay an attorney to file an amendment to your birth certificate, but it really isn't necessary.