I've done the same thing. My hands are relatively small, so I don't have much of a problem without the extension. However, the extension does make it much more comfortable in my hand. If you have a 26 or plan on getting one, I'd highly recommend buying an extender for the grip. They're inexpensive and easy to find.
These are even better, and give the pistol greater capacity as well. I have them for both my Glock 26 and 30. Bill T.