@NicolaSacco I like this thread.
How good am I? As people have said, that Harry Redknapp interview was brutally true, fans don't get to see anything behind the scenes so it's hard to know how good a youth player is. So all we get is the pro games to judge, so the few games we see are IT.
However I remember seeing Xavi play us in 1999 and thinking after 1 game that kid was gonna be special. And then Fabregas against us for Arsenal and being sad because I just knew he'd be an incredible player. But that's confirmation bias: I don't know how many players I've gotten "wrong" in that way of thinking.
But I've not had that feeling about any of the players that made their debut for us, like Chong, Iqbal, etc. Even Januzaj I always felt in the back of my mind he would be too slow to make it: with Ronaldo and his debut he was tall and FAST, so even if you don't have the skill you can hurt people... And he had the skill too.
The one modern player I've felt has that sort of weird ability is Billy Gilmour but Chelsea got rid of him so maybe my radar was off on that one after all .