We will be converting our MYW passes to APs in August, and I specifically asked about whether or not DS's AP could be used for room discounts. For the first year he will have a child's AP, and that is NOT valid for room ressies like others have posted. BUT in addition to that, the AP holder reserving the room must be 18 or older. So having a child with an adult pass who is age 10-17 doesn't help.
My original plan was to buy one AP in August, one in December, and another next March so they all expired at different times, but DH or I need to have a valid one if we are going to use it for room discounts.
I am assuming since Disney tracks so much info about us to begin with that they absolutely track the age of each AP holder.