I Am 39 Years Old. I Had An Ultrasound Scan

I am 39 years old. I had an ultrasound scan on my breasts and doctor found a fibroadenoma on my left breast. The size is 6mm x 3mm. He suggested follow ultrasound scan in 6 months time. I asked for biopsy but he said it is not possible because it's too small and non palpable. He also assured not too worry as he can tell from the image that it is a benign type. I would like to know if it is possible to do biopsy? And it is possible to excise?