um... is 15 your real age? have your growth plates closed yet? are you sure about this? what body type are you. how tall are you? how much do you weigh. what would you like out of a program - strength, size, or loosing weight? answer these questions and i'm sure someone can help you design a routine.
if size and strength is what you're after (which it usually is) and your growth plates have closed, and you haven't lifted that much, start a new thread titled "whats the best 5x5 program out there?" then ask any posters to explain why its the best. there's a few of them, riptoe, billy starr, etc. its probably the best for you if size and strength and being new to the gym sounds like you. i honestly don't know the difference between the 5x5 workouts, but i do know its the best way to get to where you want to be and its highly recommended for most beginners.
once you see the program, you'll say "that's it?" but trust me, yes, its the best, and anyone on this forum will agree that it works.