Your nipples should be growing as you grow, this includes your breasts. There is no exact age although usually around your early teens they should start to develop and then stop usually late teens. Although as I said there is not set in answer.
Yes they do my two girls are both 23weeks and they have nipples :)
because they are growing.
Some do and some don't.
Girls have nipples from the time they are born, perods have nothing to do with them.
Yes you can some girls like there nipples sucked on some don't you can
NO! i bet the person that asked this is a sick perverted moron
of corse
The nipples get larger so as to better suckle the baby.
Yes hairy nipples are normal for Men... but for girls they usually dont grow hair around the nipples.
Yes
Boy guinea pigs don't have nipples.
When the process of puberty starts , maybe around the age of 10-12 for some girls a bit later