I don't try to define myself by labels much, though the ASD one seems to fit me quite well and my diagnostician would agree. Still, ultimately even that is just a ragbag of traits, some of which I have in spades, some of which I don't. And if I tell other people I've got ASD then there's a danger they'll have a pre-determined idea of what that means that won't match up with who I am very well.
I much prefer to just observe and catalogue my strengths and weaknesses, in the same way as I avoid the question of how intelligent or unintelligent I might be and focus instead on my individual aptitudes. As soon as I try to reduce the whole shebang into a couple of words or a number, I think I just lose the essence. But my traits are fairly objective things, and I can always use a knowledge of what I can do easily and what I can't. It comes in handy when I'm deciding what to do with myself.
Perhaps unusually, I'm fairly comfortable with nihilism, the idea that my life, like everybody else's, is just a messy accident with no unifying plan, and that I'm just trying to make myself as comfortable as possible in the midst of whatever the environment turns out to be. My life is whatever I happen to make it and whatever the world will allow me to make of it. I'll probably never know quite who I am and I don't particularly need to know. I'm a father, a husband, a friend, a musician, an inventor, thinker, and "hobbyist." I suppose I used to be a professional scientist of sorts, but I never fully identified with my job. I'll never be the best and I'll never be the worst. Oh, and they say I'm on the spectrum.
So in summary, I don't struggle to define myself, I just get on with my life and don't think about who I am very much.