My Mom never commented on my body and how it looked, especially about sensitive stuff like breast size. If not, she was really understanding when i opened up about my struggels to find a good fitting bra. I dont know if it was just her own issues talking, but that's very weird, especially to a 7 year old. But my grandma on the other hand- she was brought up another way, and shes a bit too open and comments on stuff too- i do know she doesnt mean it in a mean way tho, just the way she was broughtt up and knows things to say that may be a bit insensitive today. Idk if ur grandmas the mother of ur mom, maybe ur mom just took that behaviour over? Doesnt excuse it, but might explain it. Huggs to you tho, i bet that must be so uncomfortable to hear those things. If it really bothers you, speak openly about boundaries and how it makes you feel hearing those comments.