Yes, assuming you can document that she qualified back in the 1990's. So the problem might be getting that documentation - especially if you are not currently living in the U.S. That's why you need a "good immigration lawyer".
Certified Immigration Law Specialist*
Law Offices of Tasoff and Tasoff
16255 Ventura Blvd. Suite 1000
Encino, California 91436
Her citizenship may have come about by operation of the law. Let's talk in more detail.
Myron R. Morales, Attorney
This answer is not to be construed as legal advice. For more information please contact us at firstname.lastname@example.org.
Whether your child is a US citizen depends on facts not in your posting.
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.