How do you get an immature person to admit they're incorrect?

I wouldn't recommend trying. Foolishness goes right to the core someone's intellectual makeup. Even if you could Get them to admit they are wrong, it is just scratching the surface.

Self sustaining development only comes when a person seeks new information, not when they are forced by an external force to admit fault (that only works if you are willing to police their behaviour 24/7)

I just set up my life in a way where the foolishness of others doesn't affect me. Then they can do as they please, and I only give them advice if they ask for it

You can't make anyone say or think or even realise something they are not ready to accept. You say your piece and move on.

Just wish them the best of luck in life, lmao. They'll find out the hard way.

I don't bother for long. Life is the best teacher.

"I may make mistakes, but being wrong isn't one of them!"

You dont..so be the mature one and let it go

Dab on them fools!! ┬┴┬┴┤\ᴥ•\ʔ

its not always possible

You can't

One often cant— that's part of their immaturity.