You are using or will be using the CSA-Child Citizenship Act, i.e. a law that allows you be automatically obtain US citizenship based on a law passed in February 2002 (top of my head, I think this is the date) so as long as you have a green card, and are under 18, you will acquire citizenship automatically by operation of law when she naturalizes and swears in or takes her oath. So you can apply for a US passport with a US Passport Office also with a US Post Office (but they usually get confused and don't comprehend the complex laws whereas the US Passport Office does) and then, you can leisurely apply for a certificate of citizenship which can take up to 9 months. You can be 30 at the time you apply or 90 it doesn't matter as long as your mom naturalized while you are under 18.
As far as I know the citizenship takes effect on the date of the oath. You might want to check if you can get your mum an early oath date.
Shah Peerally, Attorney at Law President of Shah Peerally Law Group PC Newark CA Important: The above is provided for educational purposes only. You should not act or refrain to act solely based on the information provided. Cases differ and success in one case might not constitute guaranty of success in your case. We recommed to talk to a licensed attorney before you proceed. For more information on call us on 510 742 5887
You question is confusing, first you state that you already became a citizen, then you ask about becoming one.
You should retain an experienced immigration lawyer, whether myself or one of my colleagues, to review all the facts, advise you, and handle the case.
J Charles Ferrari Eng & Nishimura 213.622.2255 The statement above is general in nature and does not constitute legal advice, as not all the facts are known. You should retain an attorney to review all the facts specific to your case in order to receive advise specific to your case. The statement above does not create an attorney/client relationship. Answers on Avvo can only be general ones, as specific answers would require knowledge of all the facts. As such, they may or may not apply to the question.