Friends dye their hair then call me a copycat when I did it first?

Lately my friends have all been dying their hair red and when i compliment on it, they made some snobby remark saying I copied them. Then they continuously make rude remarks about my hair. My hair has been dyed red for several months and they just dyed theirs so how am I a copycat? They say they had the thought about doing it before I did which is a stupid excuse. This tends to happen a lot because when I dyed my hair green they did it also and used the same excuse. What is more annoying is that other people join with them when there is proof that I'm correct. I don't get this.