School Fears for Mommy

Next year if all goes well Kiernan will be attending a half day pre-school. He was eligible this year but it isn't free in Montgomery county unless you qualify for head start and we don't. I want him to be in school for a few reasons. Mostly because being around other kids of his own age will really help his social skills. Like I was at his age, Kiernan is much more comfortable with adults than with other children. Being in church helps, playing at soccer-plex around other kids helps, Megan helps but none of it is true interaction. I am with him at church and the playground stuff is more co-play and observation than anything and of course Meg is too small to have brought out much in the way of conflict resolution. He is such a good boy and so gentle that I am really nervous about how he will do in the rough world of school. We had a little neighbor girl that he used to play with. She was wild and loud and really to my mind not a very good influence. She liked to talk back and pick fights, she liked to show off and push buttons. She broke some of his toys and she ran over his foot very deliberately with her bike to get a reaction out of me. He loved her. He was a little afraid of her too but mostly he loved having a friend to follow around. I am afraid of what his desire to please and his sweetness will get him into.
I am nervous about his loving flowers and being picked on by boys. I am afraid of his laughing when he is afraid or in pain, and how that will never get the helpful reaction form other adults. I don't want his feelings, so hopeful and trusting, to be quashed by the completely insensitive nature of human interaction...especially children s interaction.
I know that he will have to get used to the world and learn to deal with it on its terms 9 time out of 10. I know that I am in danger of 'mothering' him too much. I also remember how hard school was for me.
I know he is sensitive in a way that some kids (and parents and teachers) just aren't and don't get. I know that there are a lot of other sensitive kids out there and that mostly they learn to muddle through. I don't really see the value tho in making it any harder than it needs to be.
We are hoping to move to Frederick County next year. We are hoping to buy a house. We are hoping to put Kiernan into a lottery for a charter school (Montessori in this case) because from what I have seen public school is the pits.
I have a few friends that are teachers or spouses of teachers...my own father is a teacher. Nearly everything I hear about public school bothers me.
I just read  this article on a crazy but apparently routine third grade curriculum and it made me mad.
I think education in this country is so counter productive right now.
I know that as a person who loves learning and reading and science and art that I shouldn't feel this way. I know that there are great teachers out there. I know that he may very well thrive in school.
I feel that he will have a hard time because I had a hard time and I know the very limited validity of that kind of thinking. But I also feel he will have a hard time because I know him better than almost anyone in the world so I can't just let it go.
So here is the question.
What do you think I should do?
How would you help prep him?