You have three years to amend a return (or two years after you paid the tax due, whichever is later), therefore if you would like to amend your 2017 tax return, you have time to do so.
Note, though, that typically itemized deductions are only taken if they exceed the standard deduction. In 2017, the standard deduction was much lower than it is for 2018. In 2017, the standard deduction for single filers was $6,350 and $12,700 for married filing jointly. Therefore, if your itemized deductions were greater than the standard in 2017, it was more beneficial for your tax situation to itemize. Plus, last year there were personal exemptions ($4050 each) given whether you filed with the standard deduction or itemized.
In 2018, the standard deduction is now $12,000 for single filers and $24,000 for married filing joint. Therefore, for itemizing to be beneficial on your return in 2018, the itemized expenses would need to be over the standard deduction amount. Plus, the personal exemption amounts were all removed beginning in 2018. This is why TurboTax believes there will be more people taking the standard deduction this year than there has been in the past.
Here is information on how to amend a 2017 tax return in TurboTax if you choose to do so:
https://ttlc.intuit.com/replies/6603004
Plus here is more information and illustrations on the difference between standard and itemized deductions:
https://ttlc.intuit.com/replies/3302313
