To become a "witch" to many is to be devoted to the craft and to live a magick filled life. It's very much a way of life.
However there are many who can practice magick successfully without being a "witch". Magick itself is not isolated to witchcraft.
Congrats on the successful spell! But I would put a lot more concentration on learning about whatever path you wish to take and feel comfortable in your knowledge before initiating yourself and calling yourself a true "witch". Of course we never stop learning but there is a threshold of comfort we cross. And don't forget initiation, it is a very important step in every path of magick.