This isn't a "should they age" thread, or a "what fits in their continuity" thread. When you look at the characters in the titles you read (or remember), without doing any math, how old do you figure that they are?

For me:

Captain America is about 35

Iron Man is between 40-45

Thor is at least 1500 years old, but looks about 35

Hank Pym is about 45

Janet Pym is about 35

Hulk is about 50

Hawkeye is about 30

Quicksilver and the Scarlet Witch are both 28-30

Mister Fantastic and The Thing are about 50

Invisible Woman is about 30

Human Torch is about 25

Spider-Man is about 25

Daredevil is about 35

She-Hulk is about 35

Cyclops is about 30 (these days)

Professor X (would have been) about 60

Wolverine: there's no telling but he looks just about 40

Nightcrawler is about 28

Storm is about 32

Colossus is about 26

Shadowcat is about 22

Banshee is about 50