31, actually. 😉
There is a point of diminishing returns, however, as people get older. 1 year out of 4 (for the OP) is a much more significant percentage of overall education than 1 year out of 12 (for me; or 13, if you're including this application cycle).
About one year making a difference in terms of maturity, in the course of one year I was BCLS trained and ran through three codes (lost my first patient, brought the other two back from cardiac arrest); in the course of a different year, I began clinical rotations and answering ethics consults (as part of a team), so real people lived or died based on the rec's we made. These are profoundly life-changing experiences, so don't discount the value of a year. A year spent doing nothing of impact certainly doesn't make a significant difference; a year spent meaningfully does.
Regardless, age is a consideration for me, as are character development and the ability to handle the realities of medicine. And no, I don't consider the OP to be a "dream candidate"; while the research background is impressive, we don't have the raw application statistics, we don't have the rest of the primary application, and what he's described in terms of EC's are typical for applicants.
Regardless, this is neither here nor there. OP, if you still intend to finish early, best of luck.