For an example Morgan Strebler oneday thought that having a sighned coin borrowed and bent in mid-air would be a very cool effect. He then thought up on how to do it using the slieghts he knew how to do. When he putr his mind to it and used his resources he achieved is effect.
Just a tip on making a routine,
P.S. Try it. It will work
You described creating an effect, not a routine. You need to take the effect that you know and form a presentation out of it that the audience will enjoy. That is a routine. You are too young to be doing restaurant work. At 13 you are not even legally able to work and you expect to get a job being a magician in a restaurant when you turn 14? I'm sorry, but no manager will hire you. I'm willing to bet you don't have much experience. You need to take a couple of YEARS to practice and refine your magic even more, and THEN go out and look for restaurant work. I am 18 and just recently got a restaurant gig. I tried when I was 15...big mistake. You need to wait it out and until then perform for friends, relatives, or even do street magic.