Do all car insurance rates drop when you turn 25?

When I turned 25 everyone told me congrats that my car insurance rate would drop. I never heard of this.

I asked around and some people said that that is not ALWAYS true. Is it?

I use Esurance Auto Insurance. Do i need to call to get the discount. Is there even a discount. Do insurance companys automatically do it?

Hmm.
I have a perfect driving record, no accident history.

ESurance has worked out great for me the last few years, I am not asking for that kind of advice. Thank You.