I agree. I think she is being selfish and not thinking of the child/children.
I had my youngest at age 38. I'm 50 and he's 13. The teen years are so challenging and I wish I was a younger parent. I get really burnt out these days and had much more energy when I was 41(when my eldest was 13) . When the twins are 13 she will be 79. How can she deal with these challenges?
Some women have difficulty letting go of their youth and long for a baby to hang on to their child bearing years.
What's done is done though and I'm not judging. I just feel sorry for the children, just like I do for the children of teen mom's. It's not an easy job being a parent and you need to be up for the challenge. 66 is just too old. It would have been a much better choice for her to be a grandma at this age so she could be there as a support, not the main parent. When your older and you feel the need to have a baby.... a better idea would be to volunteer at the hospital children's unit, or adopt a single mom with young kids. To me, that's a much more positive and selfless choice.
Just my humble opinion.
Kate