What does the age at diagnosis tell you about the mutation?

The graph shows the ages of the women who have breast cancer, which range from ages 40 to 50. So it shows that this type of disease is most commonly diagnosed in women of these ages. Apparently, women are more prone to getting breast cancer the older they are. This is because as you get older, you lose some of your strength to fight these carcinomas so the risk of mutation grows higher as well. 
Hope this helps!

The punnett square is the device used to predict genetics.