No Witch, no matter how many years they practice will ever know all there is to know. A Witch who has been practicing longer than someone else does not necessarily make them more knowledgeable. Everyone learns at their own pace, and just because someone hasn't been practicing as long as you doesn't mean you can't learn from them. Remember that a Witch is just a person, and each has their own unique outlook and perspective. Someone who is just beginning to learn The Ways should be encouraged to ask as many questions as they want, and never have to feel that they are asking a stupid question just because the answer is obvious to you.
Witches also have a responsibility in how they present themselves to others.
Many of my friends are not Witches and knew absolutely nothing about the truth of our ways until they asked me about them. Whether we like it or not, Witches that are not 'in the broom closet' can find themselves in a position where they represent all Witches when dealing with people who do not know the truth of our ways. One Witch with a pompous attitude can cause a great deal of harm and cast a negative impression on all Witches and our beliefs. Just as someone who is half way through their first book pretending to know everything can. When asked to explain your beliefs to others, keep in mind that you might be the only Witch this person will ever meet.