Touchy subject I know

I need some Non-Binary people to explain to me the logic behind what you are.

I'm most respectful to beliefs and such, I have no problems with LGBT AT ALL. I've recently been introduced to a few things I, in no way, agree with, but respect and understand.

Non-Binary I can not seem to understand or agree with. A Person is born with body parts, already assigned to you at birth. The saying, someone can't choose or assume their child's gender asks instead need to wait until they can choose themselves makes absolutely a negative amount of sense to me.

How is it logical at all to say you aren't either male or female? "PICK ONE", my thoughts... I'm so so confused and want to understand, because this is a real thing and one day I'll habe to explain this to my daughter and need to understand for myself and what to say to her.

I don't understand, "they, them, their"... you're one individual, whatever gender that be.

My intent is not to bash or be rude, it's to understand. I have a very open mind, but this is why I'm having barriers...

Somebody explain please!