If your mother has not already filed petition for you as a green card holder, but now wishes to do so as a US citizen, the petition will be classified as unmarried adult son/daughter of a US citizen, in the 1st family preference category F1 Petitions in that category if filed today, will take about 7 years to become current for citizens of most countries. By way of comparison, petitions in that category F1 which are now current were filed on or about Feb 2007.
Answered on Mar 21st, 2014 at 11:48 AM