Interesting. So three things come to mind right away when I read this.

The first is that you're not an INFJ at all, instead maybe a mistyped INTJ? We share many similar functions, an introverted/intuitive nature, but in a general sense they don't seem to be concerned with their tendency to place rationality and efficiency above emotional concerns, especially the emotional concerns of other people. If that sounds like you, perhaps it's something to look into further.

The next thought would be in-line with the other commenters, perhaps you are misinterpreting how INFJs actually behave with how they are portrayed. I can be empathetic towards others, but so often that feels compulsory, rather than out of the goodness of my heart. I feel like this is expected behavior and to act any other way would be inappropriate, even shameful. Perhaps you are still growing into your groove in this area.

But -by far- the most interesting thing you said is that you would imitate how other children act with their parents. This seems like a really strong indication that you might have some kind physiological component to the problem. This can be cause by all kinds of things, an issue with the amygdala, trauma, chemical imbalance, personality disorders, etc. People who exhibit impaired emotional regulation like this will often report 'learning how to mimic emotion' or 'having to practice facial expressions in the mirror' to learn to fit in.

This doesn't mean that some thing is wrong with you in the sense that 'you're a bad person', simply that you might encounter some of the struggles you mentioned in your post. If, however, you start to exhibit other symptoms, like thrill seeking, unchecked aggression, disregard for the law, or feeling no remorse after mistreating others, you'd want to seek professional help immediately, as those are big red flags for antisocial personality disorder, and can lead you down a really rough path in life. (This doesn't sound like you from what you've posted by the way, so don't freak out, just something to keep it in mind.)