My cousin kept teasing me for my belly.

I went to visit family last week and my cousin (19f) whos fit and skinny kept commenting on my weight.
She has no filter and when I first saw her she kinda patted my stomach and said,
"Looks like somebody gained a little winter weight."
Later when I was fixing my hair my shirt rode up and my cousin slapped my belly and said,
"Your bellys hanging out!"
Then I told her she better be careful because i used to be fit and have a flat tummy like her.
She just poked my belly and said,
"So what happened?"
Later ahe suggested that I go to the gym with her and said,
"You can probably loose that belly by beach season. Either that or we can get you a high waisted bikini. That would help hold in that tummy for ya."