I'm not a qualified "expert", I don't have any degrees in child psychology. I studied economics and was a marketing and advertising professional for over 20 years. But now, I am a professional mom. And with four kids, I think I've got a bit of experience and have learned a few things.
One of the most valuable thugs I think I've learned is this: don't push your kids to make their transitions a milestones before they are ready.
You can force a transition - potty training, switching to a bed, sleep training, weaning, pacifiers, etc. It will be exhausting and painful and hard, and at times even sad.
Or you can listen to your children, and let them transition when they are ready. You can guide, demonstrate, gently suggest, and then make the move when they are ready.
And do you know what happens when you do it that way? It is so easy! It is not sad. It is not hard. It is not painful.
We try to fit our kids to these arbitrary timelines that experts tell us is best. But every child is different. What is best for one, or even most, might not be best for your individual child.
I say go right ahead and read the books and articles, listen to your friends and your parenting forums, get your experts and doctors best advice, and use all that to make an educated decision about what is right for your child. Pay attention to what your child is trying to tell you, they're usually right about what they need.