Of the twelve playoff teams from 2014, the New England Patriots have the third youngest unit, behind the Green Bay Packers and the Seattle Seahawks. This implies that the Patriots have the youngest roster out of the AFC teams that were in the playoffs.
That's a good sign.
In the past decade, there have been just five cases of teams making a Super Bowl without making the playoffs in the prior season (ie: 25% of Super Bowl participants, including both Giants teams), but just one case in the AFC. The 2010 Steelers missed the playoffs the prior season due to Troy Polamalu's injuries, and Ben Roethlisberger's unavailability due to a concussion. The 2009 Steelers were reigning champions, so they were definitely still a contender.
But what does that mean? It means that some other teams in the AFC might make the playoffs, but the likely representative in the Super Bowl will come from the old guard of Patriots/Broncos/Colts/Steelers/Ravens (and technically the Bengals). These teams have represented the AFC in 18 of the past 20 Super Bowls, and 23 of the past 30 Super Bowls. The Bills (4x), Chargers, Titans, and Raiders are the other appearances.
I say that just to define the term of contender because the Patriots rank 13th overall, per Jimmy Kempski's numbers at the Philly Voice. The Patriots have ranked 11th, 11th, and 9th over the past three seasons. The Dolphins rank 4th and the Bills rank 10th, while the Jets somehow have an ancient roster at 27th.
The Ravens (15th), Broncos (18th), Bengals (20th), and the Steelers (26th) are all ahead of the geriatric Colts, pulling up the rear in 32nd place.
The Patriots have done a good job of shedding their age this offseason, with Tom Brady a clear outlier on the roster. Stephen Gostkowski is the next oldest at the age of 31, so when your quarterback is coming off a fantastic Super Bowl against the best defense of the past decade, and the next oldest player is a kicker, your team is in pretty good shape.
Rob Ninkovich is 31 as well, and the Patriots have a ridiculous amount of depth at his position. Right tackle Sebastian Vollmer is 31 and New England has two one possible young replacements in Marcus Cannon and Cameron Fleming. Every other player is 30 or younger.
So long as Jimmy Garoppolo develops at quarterback (or Tom Brady continues to appear ageless), the Patriots roster is in great shape to compete for the foreseeable future.