Some local school districts provide great pre-K programs. Depending on which area of OKC you live in, you might have an option to send your child to pre-K through the public school system. Call the administation office and they can help.
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I would like to give you few links. They might help you to choose the right pre K program.
Also ask your friends, talk to parents at library or playground, people with the age appropriate children are usually well informed.