2 1/2 yr old daughter 23lbs

Anyone here have a small child? My daughter is 2 1/2 yrs old and is shy of 23lbs 33inchs tall. Average weight at her age is 30lbs. She has always been small and was born premie at 4lbs 2oz. Her pediatrician has never been concerned about her petite frame because she is steadly growing. My daughter has never had a huge appetite. Doctor does not suggest anything to help her weight gain such as pediasure. Her dad and I are not small people....we are fairly large and tall... wondering if I should take her in for a 2nd opinion. Other than her small frame she is meeting all milestones and is a happy bubbly toddler everyday ❤.