Lower stomach after c section

So I’m just over 11 weeks post, I feel like I can suck my stomach in but not the lower bit! I’m slim but when I do this the bottom of my stomach stays the same as if I have very little control over it! I used to exercise but stopped when pregnant as I was very ill!

Does anyone have any tips or exercises to help me regain control and tone over this part of my belly and is this normal ?