I've enrolled my youngest child in preschool for this year would I be able to get a deduction for this ?

Yes, you you can claim child care credit but only if used for child care to allow you (and your spouse if filing jointly) to work and you otherwise qualify. 

If your child attends preK so that you can work, then you can use the child and dependent care credit.   You will need the Tax ID of the preK.    As stated---if you are filing a joint return both parents must have income earned from working in order for you to use the credit.