I think 3 year old Kinder is a great benefit. And this year there were a couple of kids who started 4 y.o. kinder never doing 3 y.o. and you could tell the difference, half of them ended up going back down into 3 y.o. Kinder as they couldn't interact socially (not just with the kids but with the adults too). BUT I think if its not common practice all the kids would be on par iykwim? Whereas if everyone else is used to it and your child is not they will find it harder to interact espeically if pre existing friendships have been made etc.

I think socially 3 y.o. kinder is fantastic, it helps them not just with kids but how to respond well to instructions from other adults, independence with toilet skills, opening their lunches, packing up after play, group activities and also (a big part of learning in 3 y.o.) is the ability to be assertive and indpendent (these are often the two skills that would prompt the children to repeat). And then the activities are very beneficial for motor skills, started literacy & numeracy, music appreciation, imaginative play etc etc

Sometimes it is hard yes, but I think provided its a slow and steady process it will be definitely beneficial for you and your daughter.

Goodluck.

*hugs*
Cailin