Same problem, My mom naturalized when I was 14, that was 21 years ago. On July 15th 2009, I got my US passport. I went down to a passport acceptance place. I brought in
1. Foreign birth certificate
2 Mother and father's divorce decree stating that they were divorced and that I was in my mothers custody (Obviously you won't need one if parents aren't divorced)
3 Alien card
4. Mother's US Citizenship Certificate/Proof she was citizen.
5. Proof I was living with her at the time (My high school transcript)
6 Two passport pictures
7. A check for 155.00 which includes expedited service) If not expedited, it will take up to 6 weeks.
And I received my proof of citizenship which was my US passport in two weeks
I always thought I was an Alien card holder, until I got my passport.
Walk in there with the attitude that "I AM A US CITIZEN" and apply for your passport.
That's what my lawyer told me to do and it worked!
Only citizens can get a US Passport and it states in the passport that this is proof of citizenship
check out this website for info and downloadable forms to fill out so you can speed up the process when you walk in.
Passport Home
good luck to anyone and please let me know if this has helped anyone.
I was fortunate enough to find a lawyer who didn't even charge me for this obvious, simple advice that no other lawyer has exposed to me for the past 21 years.