Age I started with problems was about 18, though I always would get that hormonal,monthly lumpiness and soreness, during that "time of the month".
I have had biopsies,core,aspirations, I stated some of that in my replies to your post, take a look at them.
At around 18, I had been in and out for the superficial cysts, re-read my previous posts, please, so I do not end up repeating myself, no one likes to read someone saying the same old stuff over and over.
I was about 28 when company physical doc, noticed the lump, told me to see my gyn and then they referred me to a surgeon. I had it finally removed at age 30.
I was going to have a baby (29 going on 30) and then had to be moving, so that is why I waited till 30.
he "real lump" was unable to be aspirated, and like I mentioned before, several doc's concerns and look of nervousness was enough to convince me to go in, and just have it removed regardless, many doc's knowing my problem with breast cysts,etc. always suggested that with these kind of cysts.
The ones that appear on my mammos have been charted, which I think I previously mentioned too, they are called calcifications, not uncommon with woman in my age group (49) and have a history of breast cysts.
I always have to go for yearly mammos to keep an eye for any abnormal developments.
Most teenage and young woman, need not a worry, unless there is a history of breast cancer in your family.
On the other hand it is good at certain ages to have mammos, most gps and gyn's will advise a young woamn when.
Again stop over worrying, if you want the biopsy get it, and and if they are going to do that they usually remove the lump, too! Try to have some faith in the medical association, and what some are telling you.
Take care,
DE