Sir from my point of view your son can do bachelor of statistics from Delhi university as your son scored 90 plus du might be better option for your son .The fees is also under your pocket and it might not affect more. And your son must enroll from right now for actuarial science course . It will offer a wide range of jobs after graduation. Choice is yours. If your son wants to do bba then send him for coaching institute for ipmat which is conducted by iim Indore it is a integrated bba cum mba course . Choice is yours.