Call me a clueless white guy but it did not occur to me that a significant contributor to "why are all the Black kids sitting together" is that there's a Black meme wherein if you make friends with white people, they'll murder you for fun and the police will refuse to investigate
Your daughter just got her first period.
Do not tell her she is a woman now.
Tell her what estrogen does.
Tell her what progesterone does.
Tell her her cycle has four phases and each one will feel different.
Give her information. Not a new identity.