US citizen travel on Indian passport within 3 months of citizenship --- legal?

Hi, how did you travel go? Which passport did you use when you left usa? Please share your experience. I am in same situation as yours.
The US does not have exit immigration; the passport leaving the US on is moot. If leaving the US to India, apply for an India visa before leaving the US.
I just acquired US citizenship, received passport yesterday. I'm travelling in 2 days to India. There is no way I can renounce my passport and get Indian visa. I'm going to carry my Naturalization certificate to prove 3 months grace period. I know someone who traveled to India in similar situation. He was first stopped at Mumbai airport but he convinced Immigration supervisor and was able to leave the airport without any penalty.
How did your travel go?