Turbo Tax online is only good for 2016 returns now. You have to buy and download and install the prior year Desktop program to do an older return. There is no penalty if you are getting a refund. You have to mail in past year returns. You should just ignore what you entered in the Online version. You need to start over in the Desktop program. You can buy the prior year programs here,
https://turbotax.intuit.com/personal-taxes/past-years-products