Would he gave gotten the deal he did if he was 30-31 instead of 26?
No.
His age is a big reason he got the deal he did along with his skillset, players his age rarely hit FA in baseball.
I think his age added years to his deal and not necessarily much AAV. This is the same market that saw Sandoval get 19 million a year last year and Heyward is a better hitter than him. My point is that just based on his offensive alone Heyward is a 4 WAR player and those types of hitters are getting around 20 million a year in most cases.