The best way to earn Bitcoins are buying bitcoins with real money or gambling.
The more real money you invest the more money you can make of bitcoin.
Entirely your choice but I wouldn't really be advising a youngster to gamble it is extremely addictive and can cause money issues, there is plenty of time to discover these issues

even though some would consider being part of bitcoin is a gamble anyway.
There are other safer ways of earning bitcoin such as working for some bitcoin which others have listed already, you could also sell any old goods you have like old mobile phones or other products.