After having my first child, I've just decided that I never want another one.
Why do you only want one kid?
Having more kids would make me responsible for them in the future.
If you feel like you can only handle having one child, then you should stop at one. No matter what opinion anyone else has, you are the one who will have to raise your children, so you should stop with a number that you are comfortable with.
That is good advice and one is enough for me and my situation is unique.
I understand completely, and I am agreeing with you. You don't need to have any kids, one kid, or a lot of kids-- whatever you are comfortable with is fine when it comes to how many children you want to raise.