My mother used to do those Toni Home Perms on me...from about 2nd grade on up...after several disasters, she started taking me to the salon every few months for a perm!
Never had my hair colored or high lighted until I was about 35 (my hair completely changed color when I was pregnant). Mom never in her life (to this day, at age 65) had highlights or colored her hair, but she still perms it religiously every few months.
When my DD was in third grade, she asked me to dye her hair, and I did. Then in 9th grade, she wanted blue highlights, so we did that. Last spring, she wanted purple hair (all over). We did that. Since then her hair has been pink, purple, blue and now platinum blonde (we had to bleach it to get rid of the pink residue). Tomorrow it is going to be dyed turqoise. I am now officially, in her eyes, the coolest Mom ever.
I told her that if she wants to experiment and do something wild with her hair, NOW is the time to do it. She doesn't have a job, she's not applying for colleges yet....but I did explain to her that some teachers or other adults might consider her hair color and make assumptions about her, and she needs to realize that she might find some discrimination because the teachers might think less of a girl with green hair. So far though, we haven't noticed that at all. I did tell her that her hair MUST be a 'naturally occurring hair color for humans' before she has her senior pictures taken next summer.
I do her hair at home, because I am way too cheap to be running to the salon and paying the hairdresser for all this work.
I noticed that many (okay, perhaps even MOST) of her friends started having highlights, bright stripes or allover dye jobs on their hair right around the beginning of sixth grade.