I don't think you can look at it as "everything they can learn there I can teach at home." The same can be said with curriculum through probably middle school. I like the idea of; it takes a village to raise a child. My son has gotten such different ideas and has found different interest by going to school. Things I never thought of teaching him or had an interest in his teacher did and now my son does. He has also learned that it isn't the same everywhere. Different adults have different rules and you have to try and adjust. He has also become so independent! He gets annoyed if I try to take his plate from the table and put it into the sink "I want to do it myself mommy," is his reply all day long with everything! It also gives you a different perspective of your child. His teacher said to me that she thought Holden was ready for potty training at 2 1/2. I thought no way, but if she wants to try at school I can try it at home. She gave me great ideas, told me what she was doing at school and within 3 days he was out of diapers forever. I didn't see him as being ready but she saw a different side of him. There are many other reasons such as socializing without mommy hanging over you, getting used to a structured and routine, exposure to curriculum and etc...
Every child is different and only you know if she will benefit from preschool or not. However be weary of the teacher saying that everything they would learn at school you could teach at home. Probably if Ana goes to preschool she wouldn't be attending that teachers class anymore. I might be biased because I had to send my son to school at 2 when I needed to go back to work. So, of course I want whatever I did to be the best thing for him, but I think it really has been great for him. He goes five days a week from 9-3 and loves it.

Beth all good points. I think part of our reticence is that, at least for now, my wife can stay at home with Ana.

I guess we justify our decisions as well to mollify our own fears that we're making the right decisions.

I also think we tend to be most comfortable with what we know. And since my mom and my wife's mom stayed home with us until kindergarten, we're both comfortable with that. I think we both turned out OK.

That being said, I know many people that sent their kids to school (or day care) early and they turned out just fine as well.

Beth: I'm dying to know what the teacher told you about potty-training that had your son out of diapers in three days. Please share! I have a 3-year-old son showing no interest in getting out of diapers.

Some suggestions she gave were
1. allow your son to be in the bathroom when your husband and you are using it. I guess so they can see it's normal

2. We used a reward chart. Every time he used the potty he got a sticker. Every so many stickers got him a reward of his choice. Like a small toy from $ store, extra TV, extra trip to park, whatever is motivating to him. Also each time he used potty for #2 he got an instant reward. For my son it was chocolate!

3. Don't use pull ups when possible. My son hated the feeling of going on himself. But only cared when wearing underwear.

4. Make your son responsible for cleaning up whenever he has an accident. Of course you are helping too, but make him feel that if he makes a mess it's him that is cleaning it up.

5. Never say negative things. Such as, only babies go in diapers. Instead make a big deal in front of your son about other children his age that are using the potty. Such as, cousins or playmates you could say "What a big boy you are for using the potty I am so proud of you." I guess they will then strive to get that attention from you but it makes them feel like they are the ones deciding to do it.

Those were a few ideas she gave. I hope they help:)

I had a similar experience. The difference was, my son had already been in day care. We then pulled him out of school for a few months when I had my daughter to prevent her from getting sick and because we were ready to change schools. During those few months, my son really craved school. Although I did activities with him and we were around kids, he missed having a regular group of friends that he saw every day. When we enrolled him in school again, I noticed an immediate decrease in his level of irritability in the evening. He is so much happier!

I agree with Beth's points above of the reasons why - they are valid reasons. The social and group instruction aspects are to me the reasons why to send her now. Plus, there are things that are more fun with a group of kids, i.e., water play, songs and story time, arts and crafts etc. It's not necessary for her academic development but her social would probably increase a lot.