Eighteen-year-old Riona Krishnan Dighe is remarkably media-trained. She sits with an elegant, ramrod posture, speaks carefully, and frequently catches herself mid-answer, concerned that she might have said too much, too little, or simply the wrong thing. But after spending an hour with this year’s Miss Teen Universe Singapore, I realised that beneath this practised composure is a teenager who just wants to get things right. She has, of course, good reason to feel that way. Next month, she will represent Singapore at the Miss Teen Universe global finals in Phnom Penh, Cambodia, competing against delegates from more than 30 countries. Her…