I have polycystic ovarian syndrome too. It is basically what the name implies: your ovaries are covered in cysts. Not necessarily dangerous or large cysts that are cancerous, but it does affect your fertility. I'm guessing that you had normal periods, since you're 19 and just finding out about this. A lot of people with PCOS, like me, have no or irregular periods, so we notice something is wrong when we hit puberty. It can also cause you to have heavier bleeding than normal.
Insulin resistance is something that is associated with PCOS. That means basically that your cells have fewer insulin receptors, basically your body is desensitized to the amount of insulin you have and it can't do a good job of keeping your weight under control. So women with PCOS are often overweight, or more prone to becoming overweight, especially around the middle of their body. They also have a 5 times higher risk of developing diabetes and pre diabetes. So your doctor should be testing you often to make sure that your blood sugar levels are in normal range, because the more out of whack they are, the further down the road to diabetes you are. Your doc might even put you on Metformin, a drug that treats pre diabetes and insulin resistance. I'm on that.
You also are at a higher risk of high blood pressure and cancer of the uterus, because the lining of the uterus is more at risk for cancer when its not being shed regularly like its supposed to. This is why you would be given birth control pills or something else to induce periods if you were having none at all (which, again, I'm assuming you are). Your hormones are also off because of this disease. I believe that often your testosterone and androgen levels are high, though I'm not sure exactly what the latter means.
As for the fertility issue, here's what one of the websites I looked up said about it: "Though infertility is one of the most common symptoms of PCOS, it is usually treatable with medication...In summary, patients diagnosed with PCOS usually have an excellent prognosis." I couldn't find any statistics about how many women successfully conceive with PCOS; most cites just say that "many women" have conceived. From what I read, there's three treatments to infertility with PCOS; first, your given pills called Clomid (or sometimes Clomid and the Metformin I was talking about before) to stimulate ovulatation. About 70-90% of women ovulate with this, but only 40% become pregnant. If you don't become pregnant with this, you can be injected with gonadotropins, which have better pregnancy rates than Clomid, but also a higher risk that you'll have multiples. They may give you interuterine insemination (fake insemination, not through normal sex) to help you conceive with this. If this doesn't work, the last resort is In Virto Fertilization. All these medicines can be somewhat expensive, unfortunately. There's details about the general prices in some of the following cites.
Here are some sites where you can learn more about PCOS:
POLYCYSTIC OVARIAN SYNDROME
PCOS Infertility with Poycystic Ovaries Syndrome
Drug and Medication Treatment for Ovulation Problems, Infertility Caused by PCOS Polycystic Ovarian Syndrome
-These two are a nice overview of the infertility treatments and can give you some idea of the price ranges of the different treatments.
PCOSupport™ -This is a support group
Polycystic Ovary Syndrome (PCOS)
PCOS - Reversing Insulin Resistance, the cause of Polycystic Ovarian Syndrome
-That last one is an ad, but it has some good information too.
Hope this helped. I actually am glad you asked this, because I brushed up on my knowledge too.