What is a normal androstenedione level for women in their 20's?

Varies. For a woman in your twenties it varies where you may be in your cycle. For example, women postmenopausal have values ranging from 20-75 ng/dl. If you are having regular menstrual cycles it depends on if you are in the follicular stage where values are 35-250 ng/dl or luteal phase of your cycle where the vakues range from 30-235 ng/dl. Obviously the range for this test is broad.