My daughter is 14 years old she is if a medium build and is quite sporty, she is 5.4ft in height and 139.8lb in weight, is this a normal weight?

By the numbers, her: weight is just out of the range that is preferred for a healthy body mass index at her age. However, this does not take into account muscle mass or where she is in puberty (she may grow more, if she is early in puberty). It's best to discuss this with her pediatrician, who knows her best and can go over her eating, exercise, puberty and examine her.