Can Meemaw's age be reconciled in Young Sheldon?

Question

In Season 1 Episode 8, when they are planning the trip to the space shuttle launch, Sheldon says:

I wonder if we'll get to meet an astronaut

Meemaw replies:

I remember when I was a teenager, I had the biggest crush on John Glenn.

This takes place in 1989. John Glenn went to space in 1962, only 27 years earlier.

That would mean that Meemaw would have to be no older than 46 for her to have been a teenager then, and likely even younger, since such references to teenagerhood are usually lower in the teenage range.

Her oldest grandson is currently 14, so that would mean she was at most 32, and probably even younger, when he was born. That would in turn mean that she or her daughter (and probably both) had a child when they were 16 or younger. This seems highly unlikely, especially given that in the immediately preceding episode, Sheldon's father describes being brought home for dinner in what seems to be a typical adult dating relationship.

Is there something missing in this timeline?

Answer 1

Various sources online have Meemaw's birth year as 1923, which is apparently backed up by Young Sheldon Season 4, episode 12. Meanwhile, while John Glenn was known before he went to space, he was only selected for the project in 1959 and making headlines in 1961. Meemaw was 36–38 during that period, a solid 15+ years after she was a teen. Therefore (barring any out of universe errors), the most likely explanation is that she lied about her age. After all, who wants to say they were in their thirties a couple decades ago, married, with a crush like that?