would i be swimming in a size large if im 5'4 and about 120 pounds
If I were you I would look at a Medium. This pant is a bit more on the loose fitting size. Great pant tons of pockets, full mesh line that will keep you nice and dry. A real tried and true classic.
I'm 6'-0" 195lbs. I'm typically a large and opted for the XL instead. They're really way big. I step on the bottoms (with my snowboard boots on) and if I don't have a thick underlayer on then they're loose at the waist too.