This may occur for two reasons.

First, you may not have clicked this checkbox when you donated:

Second, if you received a notification from PayPal that you signed up for the Pre-Approved Payment Plan, but you did not receive a confrimation email from StartSomeGood and your name does not appear as a donor for the campaign you think you supported, then the pledge was not completed and you will not be charged. To support the project, please donate again. Be sure to click on the Close and Continue button to complete the pledge.