I, too, am a grandmother raising grandchildren. I am 61 years old and raising a 16 year old girl (we have had her for 4 years)and a 15month old boy who we have had since he was discharged from the hospital when he was born. They are 2 of my daughter's 4 children. The other two live with their paternal grandparents.
Even though this is not what I had planned for my retirement, I am trying to make the best of the situation. Our granddaughter is a good kid, involved in school activities and getting decent grades. She is some help with the baby, but I don't want her to have to do too much in raising him (she did a lot with her other two younger siblings when she still lived with her mom).
The baby has turned out to be our joy. After we got through the 2 a.m. feedings and sleep deprivation, I have adjusted to having him around. Don't get me wrong. Chasing after a toddler all day when I'm in my sixties is tiring and challenging, and at 8 p.m. when he goes to bed I am done for the night, but I wouldn't trade my life with anyone.
Does your daughter assume most of the responsibilities for her child, or does she dump it on you? I find that my biggest resentment is that my daughter has cheated me out of the pleasures of being a grandma since I have to be parent to her children.