Why aren't Barca able to play such fluid football despite having so much young players??

They need a better

Well thats the problem, these young players dont have enough experience at the top level so what we need is a mixture of players as we see in any other top team most of the players should be between the age of 24-29 which is consider as the prime time for a football player whereas in barca most of the players are either too young or too old

Exactly