I suppose I have perfect pitch, in that I can more often than not: * aurally identify key signatures * aurally identify chords * sing a given note on command It wasn't until I was into my early twenties that I could do this. For me, the single biggest stepping stone was building the connection between what I could hear in my head from a song that I remember clearly with the underlying music theory. Specifically, buil…
That's why tuning forks and pitch pipes exist. You need a source of truth to ground things in, and then you can train yourself to hear the relative distance between notes from there.