Ana Konjuh has just turned 15. She is already playing 18s tournaments and Futures. A girl as good as her would more likely to "fake" her age older and not younger so that she can start her professional career earlier. If a small number of kids did fake their age younger to win a few more matches in the younger division, they would surely be losers down the road. Good kids would always like to play up to improve faster. Common sense?