My bestiez bra help!?

my bestie and me have been besties for forever (we are just like twins) and we got eachother backs, she blossomed before me and i got a bra before her but she still has a training bra. i bought my bra by myself so i have no advice to give to her. she got her training bra when my mom took us shopping so we went off to the girlz section while my mom went to go look at rugs or something and my mom has no more time to take us shopping. please hlp!