Teaching child about races

I am a hispanic immigrant living in the US. My skin is very dark and my hair is black. My husband is Irish american. He is white with green eyes.

My daughter is 4.5yo. She is white with green eyes. She looks like me a lot, but the white version.

We have traveled with her all around the world, we live in a diverse community, and she's been always around different kind of people.

However, last week when I was driving her from dance class she said out nowhere "my best friend is Emma" I said "what about Isabella?". She answered "No, because she is brown. Peach people go together like me and Emma. Brown people go together in a dif group". It was like someone punched me in the stomach. I said to her "I'm brown, so I can't be in your group then" and I started crying. I never thought my kid will say something like this. Where did this come from?. I calmed down and asked her if someone told her that. She said "no, but when we do the shapes and colors at school we put all the same ones in the same group". I was shacking and didn't know what to say. We got home and we had a conversation with her and we also ordered books. I'm terrified she will say something like this to anyone and she will get in trouble or something. We talked to her about real words "white, black, asian, hispanic, etc" so she stops saying peach and brown and understands more about the real world. Idk what else to do.