If you paid the money for tuition in December, then you can deduct it in 2017.
If you paid it in January, then you have to wait until 2018 to deduct it.
You can only deduct expenses in the year in which they are paid.
Here is a link to TurboTaxMichealMc's response to a similar situation that may help.
https://ttlc.intuit.com/replies/5868164