By marking yourself as a dependent, you will be claiming yourself as a dependent as compared to allowing someone else, like your parents from claiming you as their dependent. So what you want to do is actually unmark yourself as being able to be claimed by someone else on their tax return.
To do this, please go back to the Personal info section (upper left-hand of your screen) and click Continue. On the page Your Personal Info Summary select the Edit button to the right of your name. Go through the interview questions for yourself and make sure that there is no check mark next to the line that reads Someone else can claim me on their tax return AND no check in the box next to the line that reads Someone will be claiming me on their 2016 tax return. This will make the program aware that you will be claiming yourself on your tax return.