Hi Brenda,
I am a H1B visa holder, born in Canada (from Montreal) and married a US citizen.
It took 11 months from the moment USCIS received our application in august 2016 until the interview in july 2017.
My situation is different than yours as I had been working and living in the States for over 5 years and had been dating my husband over 2 years before we got married.
I do not understand why you are waiting in Mexico and not back home in Montreal.