i've got an old MSAR but it states you cant be more than 30 years old on June 30th of the year you would matriculate. Something like that but you should check the website which you can find from www.aamc.org
see chapter 5. Generally you have to be 18 - 30, but you can be older and apply and if granted a waiver by the Adcom you get in.
Also the age limit is extended for those that have been on active duty comensurate with the duration of service with a cap at 35 years at matriculation.
Anyway, check the website, it seems that exceptions can be made to the stated age limits.