What to do about my MIL (mother-in-law).. I love her to death and we get a long really really good.?

Lately. it has been a different story with our new baby (6 months old).. She is so condescending when she talk to be about motherhood. She makes me fill like I am an incompetent mother. She said I was hurting my daughter when I was changing her in a rush in front of the whole family. She said I don't need to that because of this.. and I wouldn't do it this way because of that. Finally, I had to say something to her. She needs to stop letting everything bother her and we will do what is best for our baby. But she kept on as I was feeding my baby solids and went and got me a napkin. What is her deal?? Is she just controlling? What should I say to her to prevent any conflict?