You must be at least 18 years of age in order to execute an affidavit of support. You may petition for your spouse immediately after your marriage. There is no required waiting period. The process you will need to follow wil depend upon your husband's immigration history including his manner of entry. You can read more about family immigration at http://myattorneyusa.com/adjustment-of-immigration-status.
Answered on Jul 26th, 2016 at 3:07 PM