do warmup sets count as a set or just a warmup?

so im 14 and just started(i dont think age matters but ive been told it does in anything regarding the gym) and i go to the gym with my friend.Each time we go,the first set of the first excersise we do we use as a warmup and put light weight (eg chest say is just the bar for warm up) and we do 3 sets of everything we do with one of those being the wermup and 2 actuall sets

is this correct and does this count as 3 sets or just 2? and if so should i just do 1 warmup and 3 legit?