Wow! That seems too old for kittens. She needs to be retired.
The kittens look great though.
When I was young our first cat had a couple litters per year. That was back when spaying wasn't well known. As she got older it was harder on her. At one point she had a pair of kittens that were attached at the tail, and the tails were all crooked.
When it was time for the next litter to come she went up on my mom and screamed!
She needed help, so mom helped pull out the babies. After that mom got her spayed, and she lived to be 18 years old.
At some point a cat needs to retire!