If I remember my mom told me mens sizes are 22 + a girls size. so if a dude was a size 30 waist he is a very small guy. Most male waists are between 34 and 40 inches pant size. I'd worry more about how you feel in your jeans especially your booty and self image. I think 6 is a very good number considering the average woman is a 12 I think.
No. I don't like when people focus on numbers, especially weight and sizes. I wear around a size 8 (depending one the brand) and weight about 10 lbs heavier and 2 in taller. People think I'm small ! They never guess what my real size is.
So no, a size 30 isn't big and don't worry about the numbers on the labels.