Overweight female 32yr. At what age should I get my carotids checked for plaques?

Only if symptoms. Research has shown that screening for carotid artery blockages in people with no symptoms (such as a "mini stroke") provides little benefit and may cause a stroke. It is therefore not generally recommended. If someone has symptoms, though, it is different and testing and surgery may be beneficial. A good iphone app to see a list of general checkup recommendations is my health checklist 2012.
Not a factor. Obesity per se is not a factor. If you don't smoke, are not diabetic, and not hypertensive, your risk is very low until about 10 years after menopause (endogenous estrogen is protective). You should get a cholesterol check at least once if it's never been done.
Only if . You are symptomatic. Screening of carotids only recommended if you have diabetes and other risk factors over the age of 55-65 depending on which study you read. Please correct your risk factors. See stroke.Org for good info.