Not ageism, just common sense
"I don't have to defend what I've done. It's between me, my baby and no-one else."
Sorry, Liz, but you might have to defend it to your baby. Most people cope with their mother's death past 30. By the time your child is out of his or her teenage years, you'll be 87. If you even make it to that age - fit or not, there's a plethora of things that could kill or severely disable you, and the chances are high you'll need serious medical care before the child hits 20. A mother is supposed to care for the child, not the other way round (at least until the child becomes an adult). What kind of burden is that to leave your son or daughter?
Not to mention the social stigma of growing up with a mother who's twice the age of all the other mothers around, and has a face like a man. As a divorcee, there's no father around to help out, either. This is an act of immense selfishness, and maybe she should have stopped to consider that there's a reason she doesn't have a child (like the fact that she's butt ugly).