Tuition for preschool and K-12 is a personal expense, and cannot be deducted. However, you may qualify for the child and dependent care credit if you sent your child to preschool so you could work. Please go through the interview for the credit under deductions and credits to see if you qualify for this tax credit.
Please follow this link for more information about the credit. https://www.irs.gov/taxtopics/tc602.html