What portage worker said was obviously dumb.
However, I have to say that putting DD in part-time nursery at age 2 was the best thing we ever did. Until that point, she was the proverbial koala - never left my side, not even in baby group. Scared of other kids and would start to whine if one came close to her at the playground.
She went to that nursery a total of 6 hours per week for a full year, in a class for 18 months to 3 yro children. The before/after difference in her confidence, skills, and relationship with other kids was incredible.
What I am trying to say is that it might depend on the child. We had to push her into it, and the first hour I left her there was horrible, but it was a very good decision for us.