I really don't have much advice, my parents where the same way when I was growing up. I just delt with it, I figured it was their house and their money so I learned to live with it. As soon as I moved away and went to college I dyed my hair every color imaginable, got peircing and tattoos. To this day (I'm 23 now) my parents still have no idea I have tattoos, I hope to keep it that way! Maybe you and your mom can come to an agreement. Maybe you can look through magazines together and find a cute and trendy hairstyle that isn't too crazy but still looks cool. Plus I'm sure your mom would enjoy spending time with you looking through the magazines trying to find something.