Per IRS; a Qualified Student Loan is:
This is a loan you took out solely to pay qualified education expenses (defined later) that were:
For you, your spouse, or a person who was your dependent when you took out the loan;
Paid or incurred within a reasonable period of time before or after you took out the loan; and
For education provided during an academic period for an eligible student.
Loans from the following sources aren't qualified student loans.
A related person
A qualified employer plan
https://www.irs.gov/publications/p970/ch04.html#en_US_2015_publink1000178237
If your loan qualifies as per the above you can deduct student loan interest paid in 2015, but not loan principal.
To report student loan interest in TurboTax:
- Click My Account (Top right of your screen).
- Select Tools.
- In the pop up window, select Topic Search.
- In the search bar, type in 1098t
- Highlight it and select GO, and follow the prompts.