You can go back in your return and change that you are able to be claimed by someone on your return, and still file your return. You will log in to your TurboTax Online account, and choose Take me to my return. Once in your return you will locate the Personal Info section and click to edit beside your name. On the following screen near the bottom, you
will find the area to click that you can be claimed as a dependent by someone
else. I will attach a screenshot of that area, so you are better able to locate
it.