When can a bunny have babies?

well,

it takes a while! just wait. pluss, i think it has to be married

A rabbit is old enough to become pregnant and have babies when they are 4-6 months old BUT you should wait to breed your doe until she is at least 6 months old OR has reached mature weight and size. This is the reason that every rabbit should have it's own cage - to prevent unwanted pregnancies in immature rabbits.