In our society, the word "sheltered" has a bad connotation. When we hear it, we tend to think of people we see as being socially backward and overly naive. And that's worth considering, in thinking about child rearing. We do want our children to be able to interact on some level with others where possible, so that they can form friendships and influence the world for good. And by the time they are ready to leave our care they should also have some sense about the world, so they can be "wise as serpents" (Matthew 10:16) and not foolish.
But we don't want to make the mistake of thinking that we shouldn't shelter our children. In fact, nearly everyone would agree that children should be sheltered to at least some degree as they are growing up. At the very least, rational people believe in sheltering children physically. Throwing them out on the street to fend for themselves would be inviting disaster.
What about spiritually, then? Should we provide shelter for the body only, without regard to the spirit? Do so-called "experts" who advise against such sheltering even believe in the spirit? Let's consider well.
Have you ever considered how the Bible speaks of sheltering? It's in a positive sense. The Bible speaks of God putting a hedge around the righteous (Job 1:10), of Him being a shelter and strong tower (Psalm 61:3), of Jesus longing to gather people as a hen gathers her chicks under her wings (Matthew 23:37). These are protective things, and good things God does for His children. Doesn't it make sense that He would also desire us to do them for ours?
Don't be too quick to think you are being "overprotective" of your children. Some of those who would tell you that are out to influence them for evil.