My friend has crazy colored hair. I want her to be in my wedding but she has to change her hair color.
This sounds like a difficult situation. It is understandable for you to want your wedding to be a certain way, however it is also understandable for your friend to want to keep her hair however she would like it.
Then she just needs to practice not getting mad and complying with the bride on her special day.
The focus should be on the bride and what she wants for the wedding. However, changing hair color is something that is difficult to do. This is really a situation that you may just need to talk out with your friend.
I'm going to make her change her hair. I'm the bride and she needs to comply with me.
I agree that you should have what you want for your wedding. Understand that she may not be willing to dye it and if that's the case, you need to find someone else to stand uo in your wedding.