Cheers, I'm 25 and I have some perfect pitch issues... Questions about this get asked a lot but I haven't found something similar yet! So, playing piano for most of my life, music teachers told me I have Perfect Pitch early on. It's true that I know the 440Hz almost perfectly, and for me it's a nobrainer to determine an interval. But over the last 2 years, I noticed that it's much harder to know which tone it is - and I have a hard time finding out when a song is still playing (I have to stop it then think about it). Sometimes I'm sure about pitch but when checking it with an instrument, I'm a semitone off.
I also noticed long ago that when trying to find the pitch, I play a reference tone in my head (mostly A or C, C because of the tunning of my guitar, hear that a lot) and from there, I do the interval thing.
So, is it possible that I just have a very good tonal memory, like a "fake Perfect Pitch"? OR is it all practise? Because: Often I just know and "feel" what tone it is, and I'm sure about it. I'm confused!