Great topic. I have to respectfully disagree with you though. There is a reason there is a gap between the ages of the little champs and the adult contestants, a gap from age 13 to age 18. I think this is done, rightfully if I may add, to assist young male singers to perform to their fullest potential. 13 to 18 is about the age range in which a young man's voice is developing and, in the process, it deepens slowly. If a young man tries to sing while the voice is still trying to develop and find its range, you have a risk of cracking your voice while you sing. Sometimes, a voice that can crack easily may not be able to keep perfect sur and have trouble with the high notes. At 18, the voice of both males and females is still maturing but it has done most of its developing and transitioning from child to adult voice and the competitions can start again. You mentioned Shreya and, this voice maturity issue between 13 and 18 is not such a big deal for girls but, it isn't fair to the guys so that's why there is an age gap.