Let me explain you about life Rakib. Football players, are not bacteria. You see, bacteria follow growths that can be expressed in statistic ways, such as the lineweaver burke equation and others.
Football players, dont follow a pattern. Some players take longer to develop and turn into monsters, others peak early, some improve all their career, some are stuck at 25.
Berardi, is currently a diamond, in a fresh turd. Sometimes he shows his quality, but most of the time, you see the crap. As times passes, hopefully he'll manage to erase more and more of the turd.
Here is the deal. We dont know how big the diamond is. Or how long it will take to remove the turd.
Look at zidane, at Nedved. They absolutely exploded at certain age. Yet what you do is going like "oh this guy is better at 19 so he'll be better then them". Wel simply put : No.
Many players will be better then Zidane when aged 19. But no player will ever keep scaling that they become better then zidane at some point.