As US citizen, you may file petition for your 24 year old son. If single, your petition is filed under F1 Family 1st preference [adult unmarried son / daughter of a US citizen] It will take about 7 years to be approved and is on the assumption that he remains single. If he is married, you can also file petition for him, his wife and children under 21 years under F3 3rd preference family category. Petition under this category will take about 11 years
Answered on Jun 03rd, 2013 at 1:19 PM