Likelihood of developing breast cancer at age 22/23?

Almost never: Fortunately, women under age 22-23 almost never get breast cancer. Haven't seen any list of numbers showing the incidence of breast cancer by age year, but some articles say about 5% of all breast cancers are in women in their 20's and 30's, but most of those are likely in the over-25 age group. Probably the 20-24 age group has less than 1% of breast cancers, but haven't seen any definite numbers.