What do you think about this? I am going to exclude a friend from my life because they act immature.
Why do you think they act immature?
We were good friends in high school but they still act like a teenager and don't take things seriously.
Sometimes when people are holding us back we can outgrow the friendship and it is okay to move on to other areas of your life and not hang out with them so much. It would be good though if you could end the friendship without hurting their feelings though.
I don't really give a shit about their feelings.
It is ok to chose who you want to be friends with. If they can't grow up you deserve to find friends who are supportive and responsible.