None are correct. You are using the plural form, which implies more than one. I'm married and have one children > I'm married and have one child. I'm married and have one kids > I'm married and have one kid. I have one kids and currently she is in high school > I have one kid, and she is currently in high school.

Americans will put that comma before "and". British English tends to do as you did and not include it. :) Hence I have one kid and she is currently in high school. . "kid" is informal. Also common in English to say son or daughter, rather than child. Not always, but common.