I know that the Silver Age characters are approaching or past 50 years old and characters like Captain America are in their 70s, but in universe how old are they suppose to be based on the way they appear.

As younger characters are added, old characters have children and those children get steadily older like Stature I'm wondering how old are the heroes.

The New Mutants and New Warriors were the "new kids on the bloke" once but now they are the more senior of the junior heroes, some of them even teaching.

Spiderman and Human Torch were teenagers when their stories started, but they are clearly grown men, now, so the question is how grown are they?

Young X-Men like Anole, Pixie, Hellion, Indra, etc... are appear to be teenager like the Runaways and Young Avengers.

Who knows how old Franklin and Valeria are.

How old are Cyclops, Storm, Iceman, Beast, Emma Frost? Late twenties or early thirties?

Captain America, Iron Man, Mr Fantastic, Luke Cage, Hulk, Hawkeye, Giant Man, Falcon, Ms Marvel, etc...

The sheer number of adventures and 50 years experience makes them seem as old they are but for them its made to seem as though only 5 years has past since all this began with November issue of Fantastic Four back in 1961.