Welcome! It sounds like you belong here.
As you're realizing, it can be really hard to talk with other parents when your child is doing things that the other kids are not yet doing. People often don't believe you and, at the very least, can't identify with how things are for you. It's kind of a sad reality that you may have to limit how you talk about your DS with certain people. But, that's why it's so great that you've found us here!
Because there aren't many/any people around you who are in a similar parenting place as you are, it is important to realize that "other people" aren't the best source of parenting expertise - YOU are. Now's a great time to start reading books on giftedness (even without an official gifted identification) just so that you can begin to empower yourself. You know your son the best and, while it can be useful to observe other people's parenting and hear other people's philosophies, you have to listen to your child and trust your gut. Because very, very few kids are doing things that your DS is doing at the age at which he is doing it, very few people are qualified to overrule your gut.
As far as computer time or any activity, again, it's up to what feels right for you and your DS. Active time on the computer is much different from playing passive games. I would bet that your DS will tend to limit his time on the computer. Even if one day he decides to type on it for two hours, he'll eventually move on to a different interest. I can't imagine any 2-3 year old becoming a completely obsessed gamer. That being said, I like the idea of having a scheduled computer time, with a lot of other activities loosely scheduled throughout the day. I'd go child-directed, but an outdoor time, a game time, a quiet reading time, etc. But, it sounds like you're doing that already, so I wouldn't worry too much about this.
As far as being concerned about whether your child will know too much in preschool, he's already past that. Whether he fits in or not is a different topic. And here, again, your experience with this will be unique to your child. Start thinking about whether your DS is happy to play with kids his age or prefers older kids, whether he is happy to play or is driven to learn in a more academic way, whether there are skills he would enjoy learning at school that he is not genreally exposed to at home or in your normal activities, whether he is happy to go along with others or is more strong-willed, and what you want out of a preschool experience for him. Then, go out and find an existing program that will meet some of those needs, or create your own program if you think that will work better.
Above all, this is a time to gather information and begin to trust yourself and your DS. Nothing in life in mandatory - from limited computer time to preschool to college. So you are free to raise your DS and enjoy your DS in whatever way you see fit.
