Braces? Enamel Of Teeth? Help?

Hi, So I'm 13 Years Old And I've Always Had REALLY White Teeth. When I Got Braces 10 Days Ago, I Started Brushing REALLY Hard With Baking Soda. I Noticed That The Top Of My Teeth Started Turning A Tad Bit Yellow. My Mom Had The Same Problem, Because She Brushed To Hard, And Is Now Getting Veneers. I'm Obviously Going to Stop Brushing So Hard, But How Can I Build My Enamel Back Up?