If you have your own mum to take care of baby at least till she's about 3 years old or so, will you continue this arrangement or send your baby to school earlier. Why and why not?

I will send my child to playgroup and then nursery as per normal schedule which means between 18-24 mths I will already send her to playgroup. I believe this is more to develop the social skills and independence for the child even though my mom does a great job to take care and teach my gal.