A question about fibroids?

My mom just found out today that she has between 5-10 fibroids and that she'd have to have them removed and possibly a hysterectomy. However, she said they it could turn into cancer if they grow. But I remember the doctor saying to me that it can't. So which is it? I am 25 and I have one that I know and my doctor told me as long as it doesn't cause any problems there is no need to take it out. Since she has so many now,(she's 51) will there be a higher chance of me getting as many in the future?