Front tooth gray after root canal. Bonding or veneer?

My daughter had a trampoline accident and in the process killed her front tooth. It is gray at the top and noticeable. she is currently wearing braces and is 15 years old. She will need something cosmetic done to front tooth when the braces come off. I was told she is too young for veneer? Is that true? Will bonding work for this? What do you recommend.