What? Me worry?
You didn't need your mother to teach you that causing intentional harm to innocent people is wrong. You didn't need her to teach you that accidentally harming someone innocent isn't immoral (although you might have needed the experience to teach you that your action that caused the accidental injury should be avoided in the future).
You didn't need your mother to teach you that intentionally causing harm to someone who attacks you is justified. Your mother didn't have to explain to you that only enough harm to stop the attacker is justified. It would be wrong to kill someone in self-defense if you could stop the attack by simply restraining them.
You needed your mother to explain the various ways that one might insult people because those are things which will vary from culture to culture. But you didn't need your mother to explain that insults cause harm and that intentionally insulting people is wrong in all cultures.
You didn't need your mother to explain that justice is only possible to minds unbiased on the relevant issue. For example, you know intuitively that the sentencing of a convicted rapist would likely be unfair if done by the mother of the rapist or the father of the victim.
Your mother is/was not a moral authority. If she told you that killing is always immoral and you accepted her opinion, she misled you. Conscience does not support absolute rules like that. It makes judgments case-by-case when all of the facts of the situation are known.
Of course your mother or father or Juvie officer had to teach you right from wrong. If it were not so you would have never been reprimanded as a child or ever heard the "NO" word.