my friend,, most of the aircraft's start the right engine first which is number 2 for a lot of reason's all i can find is
You start the engine that you can hear but not see first Engine number 2 listen for any anomalies during start up ,
Next you start the engine you can see which is number 1 but not hear -you may not hear any problems with the number 2 engine already turning
but also there is a lot of reasons