Where do I find out the number of prior years that I claimed the American Opportunity Credit and Hope Credit?

Check your tax returns for the years you had qualified education expenses.  If you had claimed any amount of this credit in previous years, you'll see how much at the bottom of Form 8863, Page 2.

If you used a TurboTax Online account to file a prior or current year return, you can download the return from the Tax Home page (the after sign-in landing page)

1. Sign in and scroll all the way to the bottom, Your Tax Returns and Documents
2. Select the year you wish to access, then Download/Print Tax Return (PDF)
3. Preview the PDF and look for Form 8863.   You can use Ctrl + F (find feature) to search for 8863 or American Opportunity to find it easier. 

The times your parents claimed the American Opportunity Credit (AOTC), while you were their dependent, also count against the four times, you are allowed. You may need to ask them to check their records.