Not trolling, I just don't see why being gay or transgender automatically qualifies you as an incredible human being. Either you're a great person or you suck, being gay or transgender should have nothing to do with that.
You realize the discrimination that being gay or transgender brings, don't you? So on top of being an amazing musician, she was brave enough to come out and take steps to live her life as she wants, regardless of what others say about her. In a world where that can literally get you killed, I don't see how you can't understand that that's amazing.
And she didn't "decide to start calling herself a woman one day." (Though I do appreciate you using proper pronouns) She has always been a woman. Her physical body just doesn't show that. Look up "gender dysphoria", should clear some things up for you.