I am 18 I weigh 115kg and I am 6ft 6 and I can only bench like 40kg but I do 4 sets, where each set consists of 10 reps. I dont know how people do much higher weights, I usually limit myself to a weight I feel I can do 4 sets comfortably with and atm this is 40kg.
I hardly go to the gym so I am not to fussed, I would like to ideally be benching 80-100kg but yeah I dont really go to the gym and besides I would still probably win in a fight against a guy who benches more than me