Witches are messengers of nature. We respect and understand nature. We choose our own path and try to respect others. We are not good and we are not evil. We are only human. We choose who we are. We don't consider it; we know it. You are if you know you are a witch.
You mean like famous/well known? That would take years and years of dedication and having a few successful Witchcraft related products out on the market or just building up another form of occult reputation on your own. It would not be very easy
And in the case that you mean to replace "realised" with "initiated", then, don't worry; no initiation, in my opinion, needs to actually take place. In the case where you feel you'd gain something from some form of initiation, or it's something you'd still like to pursue, then I'm sure many physical covens would have some sort of initiation process in place; if you can't get a coven or don't *want* to join a coven or group, then self initiations can also take place.