University of Michigan Stamps admission

Hi all,
My son is just a sophomore in high school but is very interested in the Stamps program. So far he has a 3.6 unweighted (tough freshman year straight As since) and has not taken the ACT yet. I also know the portfolio is half of the application. Im wondering if anyone knows how competitive it is to get into stamps and is he way behind that he is only just beginning his portfolio? Thank you for any input-