I have good grades and extracurriculars, and it has always been a goal of mine to go to an Ivy League school. If I graduate a year early, how bad would that be for my college admissions?
Probably fine with the exception that you have had one less year to explore your options ( get the most from your ECs). More importantly, I’d make sure that whatever happened won’t happen again in college. Don’t know the details and frankly it doesn’t matter. What does matter is that you have come to terms with it and can start anew. Remember going to college early is tough in any case. If you have “baggage” it might make it more difficult. You could also graduate early take a year off and do something great then start college. Might give you a fresh perspective and confidence. Then again it might not be possible.
Even if you’ve run completely out of classes to take, in my personal anecdotal experience, having three years of high school is at best a neutral and at worst a negative.
That said, the Ivies are low-probability applications for everyone. “An Ivy League school” is kind of an odd goal, because they aren’t particularly homogeneous. Cast your net wide, and there will be plenty of fine schools who won’t blink at early graduation, if that’s what you decide is best for you.