I have breast buds, how long will they take to grow into actual breasts?

Depends. : Your age, menstrual history, and duration of buds are the important factors here. Within a year or two your breasts should be blossoming, if not check with your doctor.

Hard to say: At a listed age of 45 I would hope they have done so. If you are asking for someone else, the process from first emergence to final size could be as few as 3 or as many as 7 years. The more background information you provide, the better we can focus on the question.