Hi I would like to know if my dad could sponsor me when he gets his greencard as he will enjoy following to join benefits when my mum gets her greencard this year when she leaves for usa. So is it possible for my dad to sponsor me or will my mum have to sponsor me as she was the beneficiary of the 4th preference category when my mum's sister sponsored her.I am over 21 and unmarried! thanks!

I believe once your father gets his greencard, he can petition for you.
Or if your mother already has a greencard or citizenship, she can sponsor you as well.

You may have quite a wait, depending on the country you're from. This is from another immigration law site.

"As a general rule, applicants in higher preference categories wait less time. The average wait these days from most countries is as follows:

Type of Preference Relative Preference Category Average Wait
adult children of U.S. citizens first preference six years
spouses and children of permanent residents second preference five years for spouses and children under 21; nine years for children over 21
married children of U.S. citizens third preference six years
brothers and sisters of U.S. citizens fourth preference 12 years



But again, the wait will be longer if the immigrant is from a country such as Mexico or the Philippines, because of the numbers of people who apply from those countries. Siblings of U.S. citizens from the Philippines currently wait a staggering 21 years.