Does your daughter need you to retire to help with the baby? My sister-in-law thought she would have all the time in the world for her sons' kids but their mom's didn't go for the plan! LOL I believe they referred to her as a helicopter Grandma!
I would certainly not make a life decision without calculating how long you except to live after 65 and what your post-retirement income and expenses would be.
Maybe instead of retiring you could take a week or two off to help her out until she is up to speed.