Hi Helen,
I agree with the others, you should definitely get a ge tax license if you don't already have one. If you were to ever get caught selling, the tax department could fine you $2,000. Because you do have your items available online, the state would consider you a business. The odds of them ever catching and fining you are probably very slim, but better to spend $20 for a GE license that is good for the rest of your life than to be slapped with a huge fine.
Now, if you're talking about simply adding a DBA to your GE tax license, that is totally up to you. I would do it so that no one could use your name. If you want to go one step further to protect your business name, you can also register it with the state.
Whether you need to get a GE or want to add a DBA to an existing GE license, you can go to the SBA. As of a couple years ago, they were located on Nimitz Highway above New Eagle Cafe and Sensually Yours. The girls there are very knowledgeable. They will walk you through the entire process and answer some of the very confusing questions on the application. Just be prepared to explain to them that you sell online and let them know whether or not you would like to sell at craft fairs, retail stores, etc. The whole process shouldn't take more than 20-30 minutes unless there is a long line.
The best part of getting your GE is that you can sometimes qualify for discounts! Joann has a 10% off program for business owners and Floradec may allow you to sign up for a wholesale account.
Hope that helps :)