Iona Winnifrith is not like other 13-year-olds – she is a Paralympic silver medallist. The Tonbridge native is also not like other 13-year-olds because the swimmer was not satisfied with second place. The teenager became ParalympicsGB’s youngest swimming medallist this century as she set a personal best in the women’s 100m breaststroke SB7 final and was beaten only by a lowering of the world record. Winnifrith beat her own British record with a time of 1min29.61sec, finishing 3.60sec behind gold medallist and Neutral Paralympic Athlete Mariia Pavlova. “I was really excited going into this race…