Your SIM shouldn’t expire that fast; the Telcel website used to say it would save the number for about a year. However, never say never, Dhyana! You can try a couple of methods.

You could always purchase a small amount ($5) on your account (phone number) from afar, using recharge.com or some other service. Then you know for sure it works.

Another way to possibly make the system keep your number is to simply put your Telcel SIM into your phone for a few minutes and turn it on. You should get a notification from Telcel that your account is out of money and you need to recharge it. The system now thinks the card (phone number) is trying to be active. Purchase a top up package when you arrive. No need to actually make a payment. You can do this simple process several times during your absence.

Have a friend already there make a payment and top up your number before you arrive. That can be nice also.

I have used all 3 methods with success for ourselves and others. I find it nice to make a small payment online before leaving Canada so my phone number is actually usable when I arrive. Then I top it up at OXXO or next door at Alberto Perfecto’s.

No guarantees these will work, but it has in the past few years.
See you soon!