Thanks for the advice. One following question: if after marriage she comes to U.S. with B2 visa and I add her to my I485 application, can she stay in U.S. even after the expiration of her B2 visa?
-Depends. If the U.S. Customs officer has not limited her change of status on her I-94 when she enters U.S., she can file I-485 in U.S. and can stay in U.S. legally even if her b2 visa expires.