I think that you should try it and see.
My DD went at two, she had never been away from me. She loved it, and still does. She only does two sessions but would love to do everyday. She's very very bright and they teach her loads ( reading, writing) stuff she doesn't want me to do!?
It is a social clique already and its a comfort that she will have friends at school. She likes the independance from me, and i enjoy the time too.
I think a balance is the best for all, our preschool is very good but they can not give each child all the one to one. Its a good lesson though, your child will not get one to one at school. They prepare them for rules and order, just like school.
Send her for one or two sessions and see how she goes. Do not let people pressurise you though. My DS is way more clingy and i am shocked when people tell me to make him suffer and break him, leave him Etc ( 1.5yrs) There was an audable gasp when i told one group of mums he is always with me. :-)
He'll go when he's ready, no point in making him suffer.