I am not comfortable making this change to zsh. What will happen if I don't do it?
Will someone explain what happens if I don't change to zsh. I do not know computer that well.
iMac 27″, macOS 10.15
If you never use the Terminal, then it won't matter whether you stay with Bash or Zsh.
If you do use the Terminal, you can stay with the ancient Bash shell, as Apple is continuing to provide it.