I’m 10 years old and have a strange itchy lump under my nipple. I am worried!

There is no need to be worried. The lump under your nipple is the first sign of breast growth. This can be itchy and painful. After a while it will increase in size and you’ll get a lump under your other nipple as well. Your nipples will become bigger and the area around your nipples will enlarge. With some girls the breasts are fully developed in two years, while with others it can take five years.