I filed my return saying no one could claim me as a dependent, but I learned I can be claimed.

If you haven't received your return yet, you should wait to file your Amended (changed) return until you do. Once you have your refund, or paid your tax due (whichever the case may be), you can amend by following these instructions:

• Log into your TurboTax account
• Click on My TurboTax, this will take you to your Tax Timeline
• Under the information about your 2016 return, you will see a list of Some Things You Can Do
• In this list, you'll see an Amend (Change) Return option.
  
• When you click it, you'll be asked if you're sure you want to amend, and then you'll be able to go back into your 2016 return and make whatever changes you need to. (in your case, you'll need to revisit the Personal Info section and edit the information about yourself.)