A former office manager who stole almost $23,000 from a Largo business has been sentenced to three years in prison. Kathy M. Charlebois, 53, pleaded guilty last week to charges of forgery and grand theft. Charlebois was an office manager and bookkeeper at Temperature Services Inc., 12461 Creekside Drive, when, officials said, she forged 53 of the company's checks over nine months. She deposited the checks into her bank account, arrest reports said. Charlebois signed a confession after her arrest.