The question about whether you had a 1098-T last year is relevant only if you are claiming tuition that was paid in 2016 but reported on your 2015 1098-T.
Schools are allowed to report Tuition received in Box 1 or Amounts billed in Box 2. Many schools bill the amounts for spring tuition of the coming year in December. You are allowed to claim that the "amount billed" for spring tuition was actually paid in the year the semester occurred.
If you can't remember, leave that question blank and move on. But make sure that you have documentation for any tuition you are claiming. If the IRS can't find a 1098-T for the amounts on your return, they will write you a letter, and then you will be grateful to have proof.