Dear Anon: There are two important questions here. Let's address each separately, OK?
The issue of heredity and GYN cancers is a common concern in women. In your specific case you had one maternal aunt with ovarian cancer and one maternal aunt with uterine cancer. It does not sound like you mom had cancer--it would have been diagnosed with her hysterectomy specimen. More commonly she might have had benign fibroid masses of the uterus as these can cause profound bleeding problems. You MAY have a genetic predisposition for uterine fibroids as a result.
Here is a chart to summarize ovarian cancer risk:
No fam history= 1.5% risk
1 first degree relative= 5%
2 first degree relatives= 7%
Hereditary ov cancer syndrome= 40%
Known BCRA 1 or BCRA 2= 35-65%
In your specific case aunts are second degree relatives (not first) so unless she had a rare hereditary ovarian cancer syndrome your risk is 1.5%. Some 85% of women who get ovarian cancer have no family history of ovarian cancer!
Uterine cancer can be hereditary (eg Lynch Syndrome), but more commonly it is not directly a result of genetics.
You are correct, the only GYN cancer that is thought to be sexually linked is cervical cancer. So as a virgin you have no real risk for that. Fortunately, neither ovarian nor uterine cancer tend to be common among younger women. However a younger woman might develop uterine cancer earlier if she has had a history of many missed periods since early adolescence.
Given what you have shared (two missed flows and a too-light flow coupled with pelvic pain) I would wonder is you have a benign ovarian cyst. These commonly interfere with regular ovulations (causing period changes) and provoke pelvic pain. PLEASE go see your GYN or clinic. They will probably do a work up for an ovarian cyst including an ultrasound (ovaries visualize well on ultrasound). Given the current pain you should be checked out.
Thanks for writing.
Yours,
Jane