Well, in your example it would not be a potential explanation for her preference for pink. But peer influence is probably a likely explanation.
For the second, part of what I was getting at was that there doesn't need to be a majority if she only really identifies with a few members. The members that she thinks of as her friends are likely to have much more influence over her than the overall group.
Not saying it is likelyhood. And I agree, that majority can influence minority, especially in youngster social circles.