I would strongly suggest that you contact an immigration attorney in your area to discuss this. You can also go to USCIS for an INFOPASS appointment, bring in all the documentation and inquire a
You can work but it will not be lawful employment once your OPT ends. However, if you end up adjusting status as a spouse of a US citizen, then any unauthorized employment will be forgiven. 
You are permitted to volunteer when the work you are doing as a volunteer is truly volunteering type work. In other words, you cannot simply work for no pay and call it volunteering if it is the
Hello. You may marry your boyfriend and file for your conditional residency before your Visa Waiver runs out. The filing will allow you to stay beyond the 90 days and process in about 4 months (depend
You can file to change your name with your local court. You will also have the option to change your name when you naturalize (about 4 years). If you change your name through the court, then you will