Parenting Advice From Childless Friends
Your friends are probably either just making conversation or trying to be helpful when they give parenting advice. Friends' advice is almost never a pointed critique, so as annoying as it may be, try not to take it personally.
It is up to you to take it or leave it. Getting into a big debate—especially with someone who doesn't have kids—is rarely worth the effort. When you are discussing a problem or parenting issue with your friends, be clear about whether you are looking for problem-solving help or just a sympathetic ear.
Sometimes your friends will have good ideas, so it is worth staying open-minded. As you develop confidence as a parent, you'll learn to let unsolicited advice roll right by without bothering you so much.