Update:

AOPA has sent a letter to FAA requesting a change to allow the Student Pilot application request to be accepted up to 30 days before a student's 16th birthday:

http://www.aopa.org/-/media/Files/AO...PAR-letter.pdf

AOPA says a workaround for 15 year old Airplane pilots would be to apply for the Student Pilot certificate be checking the Glider category on the application form. The Student Pilot certificate is issued without any aircraft category.

Of course, this workaround will not work for Glider Student Pilots ready to solo on their 14th birthday.