Twin measuring small

Mrs. Adams • Currently pregnant with my rainbow fraternal twins after 9 long months TTC. God please be with my babies and I. Lord knows I love them more than life already 😍👶

My twin A was measuring small around the abdomen yesterday for my 24 week ultrasound, she is measuring 23 weeks 1 day. Should I be terribly concerned? There is a 20% discordinance the tech said they don't worry til 25%. But she keeps getting further behind :/

(Twin A is Lilah)