| I don't believe you are allowed to apply again, as then.. everyone would go that route.
There is a senior year for a reason. Unless you have extenuating circumstances (you're running out of courses to take at your high school in every subject, and your senior year would consist of one academic course and 7 study halls, you're more than 4 years ahead in math...), I would definately recommend to wait another year. One more year means a lot in maturity and in general critical thinking and writing skills. You might gain a lot from taking courses at your high school that you wouldn't normally take.
I was once in your position. I didn't really have a reason for wanting to get out of high school other than boredom, and excitement for the application process, and I thought a lot about the decision. You really only get one chance (applying after a gap year usually is not too successful) to apply as a freshman to college.
I'm now about to enter my senior year in high school, and while I am exhausting my school's list of courses and have been taking math beyond what my high school offers, I would say that I probably will still learn a lot next year. While I'm jealous that many of my friends are going to be at college this coming fall and that they already know where they are going, I know that I've probably made a better choice. One more year can help your application a lot and better prepare you for the college experience.
Many CC-ers do have the knowledge and skills needed to academically succeed at the top colleges before their senior years, but most do not choose to skip the senior year. It is an experience in and of itself. When there is no real benefit to going to college earlier, rack up some extra AP/dual enrollment credits and enjoy your senior year.
PS. At my school, there have been 2 early graduates in the past 2 years. Both are academic equals (3 years ahead in math, AIME but not USAMO, similar GPA in similar courses) and have near-identical extracurriculars. One was rejected from all of his schools except his safety and his number one. The other was rejected from all of his schools except his safety. Both are attending top 75 universities, but one had a much better outcome. It's a gamble. | 
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