what is fore skin of ur penis and what is the difference between a circumsized and uncircumsized penis as in how they look im so confused

mine had the base of my penis then at the top my penis head, there some skin thats just slightly looser and alittle darker than th rest a like away from the head but doesnt go near the head? im confused i dont know anything im 14 by the way and ive never been explained this

please help me and be mature i feel like a idoit for not knowing