2 years ago I changed my last name without telling any of my family members. I haven't changed any of my papers yet (driver license, passport, social security card). Yesterday, my father got married and asked me to sign the marriage certificate as a witness. I signed it using my previous last name (which I chose to keep as my middle name. Sorry, that might be confusing. My first name is the same, my old last name is now my middle name, and then I have my new last name). Does me signing the marriage certificate with my old last name make it invalid?? I'm kind of freaking out right now. I didn't even think about it until someone brought it up to me this morning. Please, if you know anything about any of this kind of stuff, help me.