Why do I have a line around the “ab” area when I still have fat on my stomach?

I’m a female, 23 y.o., 5’6, 140 lb. with stomach fat (I retain a lot of fat there so I wear high waisted jeans lmao) so I most definitely do not have a low enough body fat % to have abs. Are these abs (which I doubt) or just fat distributed in a weird way or what? I’m not sure what else to type because I need to have a longer question but don’t really have much to say. I started at 155 lbs. so I lost 15 pounds which is good? I want to get down to around 130. Really not sure what else to type.

Here are crappy pictures (please excuse the blotchy fake tan):