A "self" as a rigid concept only exists in your mind, like so many other things about reality. There are concepts we're so used to that we can't imagine the world being different, without them. "Male" and "female" are two of such concepts, and so are "biological sex" and "psychosocial gender". If any of them were to change, the world won't change: only our perception of it would.

I am what I am, at any given moment. I have traits come and go as I develop under the circumstances I have, and I have existing traits vary for the same reason. If I change myself right now into something I so radically different I can no longer associate it with the self I considered myself being right before the change, ultimately, my self won't change: I'll still be me, at any given moment; it's only the idea that I was once something different that would mark the change and build the history.

I have the opportunity to remake myself: I do it, bit by bit, every day. I believe in ideals to be striven for: kindness, compassion, understanding, acceptance, among others, - and I believe that striving for them will certainly make me a better person, the kind of person I'd be proud of being. If due to those characteristics I will also make someone's life a bit better as I live, that would be even better. There are also parts of me that I don't want to exist in myself, at least not prominently: selfishness, impatience, greed, anxiety, - and for those, too, I do a step every day, but a step away.

A single "self" holds you back because, ultimately, you want stability. Stability of the self is very important, but more important is understanding that there are no rigid concepts, not for one person's mind. Things change, begin and cease to exist; holding on to a single idea of the person you are prevents you from being a person that you're better off being, because there's always a strife for you to become better in you.