I remember in the late 80’s, early 90’s reading a comic book that shows this sort of wimpy average man who is cowardly and afraid of doing anything, but he says “there comes a time when a man’s got to stop being a worm” and then does something. That phrase is the them for the issue.
I can’t remember anything else from that; it was so many years ago. Maybe it was from the Beyonder series? Or some Punisher? Anyone who is a comic book expert remember this quote?
It does sound like something associated with Molecule Man…maybe his two-issue appearance in Avengers in the 80’s or Secret Wars one or two.
If I remember correctly, it was a Thor comic, in a story set in the Wild West.
Sometime in the 1880s, Loki steals Idunn’s apples of youth. He hides out in a frontier town in Texas, with his minions disguised as a gang of cowboys. He takes over the town like a robber baron in an old Western movie.
Thor tracks them down, but he is aged and weak, and nearly gets beaten by the bad guys. At the last moment, the wimpy mortal takes action, and gets one of the apples into Thor’s hand. His youth restored, Thor trounces the bad guys, restores law and order to the town, and rides off into the sunset.
It probably wasn’t Mister Mind.
The worm that matures into a Chronal Butterfly and eats reality? Lucky us. 
Do you remember why Thor was old and aging?
Haven’t read the book in question, but I’m guessing it was a lack of apples.
(Asgardians aren’t immortal by nature - it’s the magic apples that give them eternal life and youth, but if they don’t eat them periodically, the effects wear off.)
So Asgardians, sans apples, age really quickly? Or is there some rebound effect when you don’t eat them?
Surely Loki didn’t keep it up for long enough for Thor to age naturally by human measures, right?
The comic never said how long the apples had been gone. When Thor first appears in the issue, he is a middle-aged-to-elderly man. Still tougher than a human, but not enough to fight a gang of Asgardian minions in their prime. He might have been searching for several decades before he tracked Loki down.