I am a woman who knows what she likes, and has had all too many experiences with men who didn't seem to have the vaguest idea what they were doing between her legs.
Eating a woman's pussy is about the most wonderful thing you can do for her. It makes her feel loved, admired, sexy, and of course it makes her cum like crazy. Many women prefer it to intercourse, and for most, it is the easiest way to cum with a man. You may have the littlest dick on the planet, but if you give great head, you will be appreciated as a fabulous lover. Yes, it's that important. Besides, lots of women expect it these days - you might as well know what your doing.