I have asked this question before and there is no reason not to ask it again. When people ask you to describe a witch, what do you hear? "Well, first of all, they wear all black except for their red and white stripy socks!" is probably the firm answer you will get from most anyone. And I admit that on a few Samhain celebrations I have embraced the Witch Hazel in me. Besides, black is so slimming and sexy. But the truth of the matter is, there simply is no correct ritual dress code for the working witch. One of the rules of thumb is dress in clean clothes, wear clothes that symbolize the magical part of you, and realize that color has meaning. Red can be healing or protection, black can be binding or new moon spells, purple can be worn for divinations, white for dedications or purifications. Greens and golds can be worn for fertility and handfasting, and silvers and metallic golds can be worn for wiccanings (or christenings) Whatever you plan to do during your ritual, think of clothes or colors that suit the occasion.
I have spoken of this briefly and it has to do with skyclad. Skyclad is being naked. If you are a minor and are joining a coven and they demand that you have to have to be naked, get away from that coven, no coven of the Craft that follows the Wiccan Rede will demand nudity ( most Wiccans won't allow you to join until you are in your majority anyway) And no coven will demand sex as the entrance fee for your acceptance into the coven. If they do, get away from them. Even sexual rituals are private affairs between the High Priest and Priestess and do not involve the direct energies of the coven. There are some Gardnerian tradition witches who do skyclad work and that is something they do if they have adequate privacy and the weather is with them. But skyclad has fallen out of fashion right now and like all groups and systems it will take a while for a another nudie witchy movement come back round. Even Raymond Buckland states that there is some mild but none the less infantile curiosity about your Witchy Brother or Sister's shape under their robes. One word of warning. If you are wearing long ritual robes, capes or dresses, be very careful with candles, fire, incense, and cauldrons.