To start with, considering your age you may want to first apply for a student visa. With a degree from a US university, you would then be well positioned to pursue a temporary work-based visa (such as an H-1B visa), which could ultimately lead to an employer sponsoring you for a green card.
The path is long, but by taking one step at a time, the end result (i.e., getting a green card) is a very realistic possibility.
Good luck!
Attorney Edward Weiner
http://www.immigration-aux-usa.com