Doctors, what role does fish oil play in a woman in the 30 thirties? And for the skin.

A lot of good stuff! I have a great book for you to read: the omega-3 effect by william and james sears. I'm a big proponent of omega3. It improves mood disorders and brain function, softens and smooths skin, may lessen menstrual pain, one study showed improved fertility rates, low omega-3 has been linked to pcos, when taken during preg. It decreases premature birth rates, helps in controlling obesity-on and on :-).
Fish oil. There is precious little controlled data showing that fish oil is a positive for anything. There is a lot of predominantly anecdotal evidence for various conditions. Fortunately there is also no evidence that fish oil is harmful unless there's mercury or other toxins in it. If you try it for something and it seems to help you, there's no evidence it will hurt you in small to moderate doses.