I think your mother has very little to do with it and society has a lot more to do with it. Both my parents (my entire family) always told me I was so pretty. Que bonita, que linda, they would say but I never really believed them. Everything I saw in the media told me otherwise. The American stereotype of beauty was very different than it was in Mexico and than it is now.
I grew up watching Marcia Brady comb her long blonde hair and played with the fake boob blonde barbie and watched Marilyn Monroe and other tall big chested blondes in musicals and started thinking I was ugly because I didn't look anything like that and never would.
It's taken years of self development to undo that damage. People think the media isn't that damaging but it is and those beauty and body stereotypes are still so present (Brittney Spears, the Playboy girls, every Disney princess even the ones with darker hair, fitness models, beauty queens).
It's ridiculous how much beauty propaganda is hurled at you daily. This is the reason so many girls have eating disorders, become sexually active at a much younger age, have drug or alcohol problems, attempt suicide, etc.
I think the media is about 80% to blame for women's body image and self esteem issues. It doesn't matter how smart or skilled you are. If you don't look like they say you should look you're made to feel like an ugly loser. The good news is there are now many sites where girls can get help so girls today don't need to continue to put up with this.
Check out Stop Hating Your Body on FB