Well, if you take a child on TV or in real life - children are rather common - imagine how old 46 would seem to someone who is 15 or 10 or something. Such a kid might find it hard to imagine being so old as to be three, or four and a half, times the child's present age. Draw a graphic with a line 46 years long compared to one 10 or 15 years long. Majel Barrett age 46 might seem like an old lady to a child age 10 to 15.
Now remember that a child age 10 or 15 is actually rather old for a member of the species Homo sapiens. A child age 10 or 15 has already lived longer than the lifespans of many billions of humans, more than half the humans who were ever born. A child age 10 to 15 has already lived tens and hundreds of times as long as the lifespans of many millions of humans. So from one way of looking at it, a child 10 to 15 years old is incredibly ancient and old for a human, and someone several times that age is even more so.
