My Body Image around my daughter

I'm overweight by 80lbs and I carry most of it in my stomach. When I was pregnant with baby #2 my first born loved talking to the baby in my belly, stroking it, rubbing lotion on it with me. But now that baby is 18mths and my 4yo keeps wanting to jiggly my belly and play "baby" with me. She looks at me getting changed and says, so innocently, "you have a big tummy, like you have a baby in there".

I NEVER say "fat, diet, ugly" etc. I feel like I'm so careful to not discuss my body issues in front of her, but all I can think to say is "let's not talk about mommy's tummy, mommy feels embarrassed." But I don't want HER to feel embarrassed about her tummy! I guess I'm just worried despite my valiant effort to break the mom body shame, she'll still get the message that fat is shameful.

What am I supposed to say or do?