By the looks of your profile information on this question and your main profile page, your edit has been successful.
However, in case others have this same question, here's an answer. To edit your professional or buyer/seller status on your profile, please do the following:
* Access http://www.trulia.com/account/settings/ to navigate to the My Profile section of your account.
* Select the option to [+] Edit personal info.
* Select your correct status from the "I'm a" dropdown menu and be sure to save your changes when you're done.
Please let us know if you have any other questions or feedback for us.