Mil overstepping and keeps giving unwanted advice

I want to start off by saying that my MIL is in her 60’s and is from Mexico. Between her and I we don’t see eye to eye on a lot of things. I want to say some of our issues is cultural but it could also be that she is old school.

My husband and I we have an 18 month old daughter and I am currently 12 weeks pregnant. The past couple of months but it has been more consistent lately her telling me I need to potty train my daughter. Her reasoning is because my daughter will fight us, cry, and basically being a toddler while we change her diaper. Everytime she mentions it my husband and I both tell her that our daughter isn’t ready to be potty trained. She shows no signs of being ready just yet beside throwing a fit when we go to change her diaper. My MIL will then tell us she is ready she is smart and she needs to use the potty.

How do we get through to her that we will do as we see fit with our daughter or at least get her to see our side of things? This isn’t the only issue we have had but this is the one that has been brought up the most.