Hi @Coco65 sorry that you have to go through this, welcome to the forum, all of the ladies here are wonderfully supportive so you have come to the right place.
I am currently 11 days post mastectomy & mine wouldn't have been found other than slight changes & getting a mammogram. It is a very frightening time for you, but good that they have found it early.
It's all a bit of a whirlwind once you get that diagnosis, it's wonderful that your husband is supportive. There are groups here I believe for teenagers, and in the My Journey kit they can send a thumb drive for them. I hope that they can also find some support for them somewhere, it can be a difficult thing for them to get their head around too.