One of my novels is published on kdp and it has been enrolled in kdp select for more than 90 days but I recently changed the price and I received an e.mail congratulating me for successfully publishing the book and enrolled in kdp select ... maybe it's normal to get this mail even if we just made a change in the metadata but does that mean that my book started a new period of exclusivity or was the initial period (with the former price) sufficient?
If you know the answer, please, tell me.
Go into your bookshelf. Click on the green checkmark on the far right side that says "info". That will tell you when you expire on Select. Odds are you didn't uncheck the auto renew and you're in for another 90 days. You can uncheck it now so you don't auto renew next time.