Here are my thoughts...
My older dd (now 5) didn't start preschool until age 3. I researched schools very thoroughly and thought I had chosen the right one, but it ended up being a poor fit. The teacher had "never met a child" like dd (who's heard that before
) and couldn't deal with the combination of my child's deeply felt emotion, endless energy and continual reading aloud of the lesson plan. I can joke about it now, but it was very stressful at the time because I feared my dd was starting down the road of not liking school and getting the take away message that she was poorly behaved. We moved her to a local gifted school mid-year (a much better fit) and she has thrived.
DD3, started school at 2.5 ... but at the new gifted school which turned out to be an excellent fit for her as well. She loved the entire year.
My point being, I don't think age matters as much as the experience they're having at the school itself. It seems to me from reading your post that you may not be confident about the quality of this preschool.
I know you mentioned you live in a rural area away from other children. I'm sure that makes it tough to find friends for your little guy. But I would encourage you to try as hard as you can. Even if it's out of your comfort zone to approach someone at say "library hours", it could be worth it for the socialization. I have lived in a few different areas since having children and in each location I have "founded" a playgroup. And loved it. In one area, I started one with women I met at a breast feeding support group. I have approached other mothers at the library or at a park and found most of them very receptive. Perhaps they feel as isolated as you.
Again, just my 2 cents.
