When should i stop breastfeeding??

My son is almost a year old now, i am currently breastfeeding and dint start any outside milk yet. Every one(family & friends) is suggesting to stop breastfeeding( n start cow milk) as he gets used to it and its difficult to stop at later point. Some one also commented that babies dont get any benefits from mother’s milk after one year age.. is this true? Until what age breastfeeding is good for babies? Few ppl also suggested to start cow milk along with breastfeeding. What do you guys suggest? I will check with doctor too but just checking others opinion.