As the title says, my DD2 has always been a skinny little thing. She's 4.9, weighs 14.1kg and is 104 cm tall. Online calculators give her a BMI of 12.9, apparently below the 1st percentile. However, she did have the reception weighing and measuring programme back in January and I didn't hear anything, so presume that she 'passed' as a healthy weight. Maybe because she was dressed, whereas I've weighed her before bath so usually naked or just knickers?
She seems healthy enough, bags of energy etc . I'm a bit of a natural worrier though.