3 years ,36 months for production ,too long , we are not doing f 35 saga ,nor j20 saga , it's different.
China delivered first production aircraft in 2015 , lrip one , even though they were bit unclear on it's problem and aspect , like ws 15 ,etc .
We are clear from start , we want a flying bird with given parameters to be achieved in mk 1 , and full exploitation of capability in mk 2 , no mumbo jumbo claims , no too weapons claim , only what is possible , also we are testing prototype , when china developed f 35 ,it was over ambitious on operational paramters like inter operability and all.
Koreans too took a intelligent route , we are more advanced and confident took some more risk but better aircraft overall