Worried about acting the age?
Immature people keep up the stigma about acting the age, as all they have is acting.
I have a weird profile of ages when I stopped a certain immature activity.
I played legos until 13, I climbled to the tops of buildings to the age 10, stopped seeing sex as source of immature humor at an age 11, etc, only to continue sex humor later at an age 30 or so.
The Simpsons, South Park and others can entertain a person of any age. I've stopped reading most comics though. They seemed to not have a thing to offer until I found out adult comics like XKCD, SMBC, Oglaf, S&H and many others.
If a person cared what content their selected comic provides for them, they should check it. If it's good for them in terms of "mature", "adult" or in any other flavor, they should read it. If it's not, they should not watch it, regardless of these age issues.