I am currently in the US as a tourist. My b1 visa will expire on 2018. Both parents are green card holder , while my sister is a US Citizen. I’ve been flying back and forth as a tourist since 2008. I’m 38 years old and single. My question is if any of my green card holder parent can petition me? How long will it take? Both parents are not working. If they file a petition now as a green card holder, will that affect my existing tourist visa which will still expire on 2018? Will the filing of petition cancel or terminate my B1 visa? (Cause I’m still planning to go back here nbefore 2018) if I apply for student visa pending my parents petition, is is possible or will there be any conflict? Thank you and looking forward for your prompt response.