Question: I'm a sophomore in high school and have the full intention of graduating early, in three years, instead of four. My GPA is very good. As a matter of fact, I am second in my sophmore class of 500+ and I also participate in sports and other extracurricular activities. I would really like to get into an Ivy League school, but what are the chances that they would consider me, especially since I am graduating early?
I see no reason why you couldn't be considered a viable candidate for college admissions one year early. However, keep in mind the intensely competitive applicant pools you'll face in the Ivy League. I don't think your early graduation will have as much an effect on your chances as your overall profile will.
Students who "go the distance" will most likely have more extensive EC profiles and possibly more depth in their academics. Also, some admissions offices sometimes ponder whether or not a year-younger applicant will have the overall maturity and experience to deal with not only the challenging academics but also the social issues. It's not a clear cut situation and the answer to your question will vary from college to college, depending on their overall policy of dealing with younger high school graduates.
Your best option would be to call the admission offices of some of your candidate schools and ask them their take on your situation. Find out from them first, before you make any hard decisions about graduating. Consider all the angles. Best wishes on your college quest