T.K.
TL
I think it is a question of the child's readiness - not what worked for others. I did a Mom's Morning Out with my middle son and he was fine in that when he was about 2. Just before his 3rd Birthday we enrolled him in a preschool program and he was okay for a couple of months, and then he didn't want to go anymore - even though his older brother was in a Pre-k class right next door. My youngest son has been in pre-school all year this year (he was just over three when he started) and loves it. So if you are ready to try it with her, go ahead, just be aware that she may not be ready and you may need to pull her and wait a while. My theory has always been there will be enough things that the kids have to go to as they grow up, why make them unhappy at this age - unless it is absolutely necessary.
Good Luck
T.