Many send their child to preschool because they fear their child will not otherwise be ready for Kindergarten. Parents look at the long list of Kindergarten readiness and immediately feel they are ill equipped to fulfill those objectives with their child. There is no need to fear that you are unable to prepare your child for Kindergarten. There is no need to feel that preschool is the only way to properly prep this integration into the school system. There are common elements a child will need to be prepared for Kindergarten but nothing so complex that you cannot teach your child at home.
As a homeschooler and someone is no fan of school systems, I never see a big need to send a child off to school much less preschool. However, that is me and possibly not you. You may be concerned with what a child needs to know to survive her first year of school. Perhaps preschool sounds like a solution. Preschool is better than a standard daycare as it focuses more on learning and tries to keep the children engaged. However, if you are only considering preschool due to Kindergarten requirements then you have nothing to worry about.
What does a child need to know for Kindergarten?
Can your child listen to instruction?
Can your child spend time away from you?
Can your child complete projects on her own?
Can your child communicate wants and needs properly?
Can your child take turns?
Can your child learn to respect other children and their belongings?
Can our child count to 10?
Can your child recognize the ABCs?
Can your child hold a pencil correctly?
Can your child follow a routine?
Basically you need to be logical in your approach. A kindergarten student will be expected to follow directions, sit and listen, count, recognize ABCs, cooperate with others, and spend several hours at a time without mom or dad. All of these skills are easily taught in a home environment.