As careful as you are, it's all too easy to gash your thumb while carving. Wearing a glove is just too clumsy, though.
woodworking technique shop tip

Don't wear the entire glove, just a part of it. Cut the fingers from an old leather glove before you throw it away. Then, just slip one onto your thumb whenever you carve. Always endeavor, of course, to keep your thumb and fingers out of harm's way.
—Maurice Anderson, Denver, CO