"You're not going to pay a dime more for any service repairs over a 3 year period. You can even renew your AppleCare later on for further long time total coverage!"
According to the above source. However, actual text for the agreement states when searching "renew:"
j. Apple is not obligated to renew this Plan. If Apple does offer a renewal, it will determine the price
and terms.
Bottom line is that you can ask Apple before your current agreement expires.