Generally girls reach puberty before boys and there is a stage around about 13-14 when many girls are taller than boys as they have started their growth spurt earlier. This also has the effect that girls mature psychologically earlier than boys so the stories about “stupid boys” have quite a basis in truth. It isn’t a fixed rule though and all sorts of factors can play their part – general health, nutrition, ethnicity. It is a fact that puberty for both sexes has been arriving earlier as the general health of the population has improved. The age of consent at 16 was set at a time when that was about the time that girls reached puberty but now it is generally at least 3 years before. The main hormone involved in puberty for girls is oestrogen and that for boys is testosterone.
Gosh that all sounds a bit technical but I hope it helps a bit.