Because if you start slightly red and then get deeper, there may be two reasons.
1
Physically developed, when girls are younger, their nipples and pudendal parts are slightly black, which means that you are slightly red, but a large part of them will gradually darken or even become darker because of their maturity. This is a normal phenomenon. There is nothing to worry about. Only the color has changed, and everything else is normal! )
2
It may be during pregnancy, because the signs of pregnancy are different, and a large amount of estrogen is secreted, and it is necessary to enlarge the uterus to conceive a baby. So the color of the vulva will become darker. .
These two points are normal. There's no need to worry.
I hope my answer is useful to you. . .