it really depends on the child.. some kids start day care centers at 6 weeks old.. it is the only life they know.. and they do fine.
I personally worked in a day care and it seemed like the kids that were 1-2 years old often had a very hard time adjusting to the day care. But of course some kids did great on the first day. But by age 1 or 2 the kid knows what they want but may not be able to tell anyone yet.
I have my 16 month old daughter at home with a nanny. I thought it was important for her to be home for the first winter- so she wouldnt be sick all the ime... but now it is spring and she is walking and starting to talk so I would be fine with her going to day care at this age.
I would think a home day care with 6 children or less would be a good transition for your child rather than an large commercial center with 100 kids.