question about changing maiden name into marriage name in the middle of cr1 visa process if 1st petition is already sent in maiden name

I do not believe that American consulates and embassies would be confused by a person just married who now wants to use the married name instead of the case with which she started the case. You should of course notate all names used in any communication with the consulate or embassy. Whether the consular officer ultimately will allow use of your married name on the final papers will probably be within his or her discretion. Due to the limitations of the Lawyers.com Forums, Alan Lee, Esq.'s (the "Firm") participation in responding to questions posted herein does not constitute legal advice, nor legal representation of the person or entity posting a question. No Attorney/Client relationship is or shall be construed to be created hereby. The information provided herein by the Firm is general, and requires that the poster obtain specific legal advice from an attorney. The poster shall not rely upon the information provided herein as legal advice nor as the basis for making any decisions of legal consequence.  

Hello. It will be OK. It will also depend on what stage you are at. Your applications and letters from them will likely remain in your maiden name, but you can ask that the visa be issue in your married name. You should complete the DS-260 with the National Visa Center under this name as well. Best of Luck.