Twins

The other day I was walking through a store pushing my girls in a car car cart, as my oldest daughter likes to call it, when a woman approached me. She said I had adorable girls and asked me if they were twins. I stifled a laugh and told her no. She wanted to know how far apart they were in age. I told her they were three years apart and she was shocked. I told her they were ages 2 and 5. She gave me a look like she didn't believe me and walked away.
I know my girls are very close in height, K is a little above average for her age measuring at 44 inches tall. L is extremely above average for her age measuring at 41 inches tall. Since February L has grown 5 inches and K has grown 2 inches. I can understand the height thing throwing this lady off, but I really don't think they look anything like twins. What do you think?