It is literally “first” time, not every time. Thus if your worry is that you cannot do fast iterations in Julia where you plot multiple times, then your worries

It is literally “first” time, not every time. Thus if your worry is that you cannot do fast iterations in Julia where you plot multiple times, then your worries are misplaced. Second, third, forth etc plots in Julia are fast. Likely faster than any of the competition as it is running highly optimized native code at that point.