I wouldn't. If you have so many AP/IB/PSEO credits that you can graduate early, use this to spread out your classes throughout 4 years - taking fewer credits per semester. This makes it easier to handle tough classes like physics or o chem and also gives you significant free time to get involved in volunteering, clubs, research, and other things that will buff your app. If money is an issue, graduating in 3 years is understandable. But believe me, if you have to have multiple semesters at 17 credit hours per semester, it will be difficult. And also, as other people have said, maturity is a strong influencing factor in being admitted to a medical school.
In all, graduating early won't win you points but you won't lose points either. Its poses a risk though if you have to break your back to do it.