So, Raman is 33 now and Ishita is around 28. It also checks out with the fact that senior Mr. Bhalla once said he's happily married for 35 years and Mr Iyer once mentioned he's married for 34 years. I'm guessing Vandu is around 32.
Don't pay any heed to Subbu, he's delusional anyways. Who hovers around his ex-gf when he just (six months ago) lost his only child??