Karen linked to this great post recently. It is over three years old, but full of outstanding truth. From On daughters, college and nouveau patriarchy regarding not allowing children (and especially daughters) to attend college (bold mine):

And this, I think, is the real objection to college: the fact that by attending it, many children have succumbed to this assumption. Thus, say the most careful, we must not even look the temptation in the eye; we must keep our beloved families close, where we can watch them, where we will be sure to never stumble. But this, my dears, is a great fallacy. People do not do stupid things away from home because everywhere away from home is stupid, but because people are stupid. If you require the security of a family’s rules to be good, your goodness is definitively based only on environment, and, likely, there’s a lot of error boiling already under your skin. Pride, for example, or lack of love for your enemy; two cherished Christian sins, damned in scripture more than drunkenness or sleeping around.

While I do think there are some very good reason to consider keeping younger children out of school, by the time a person has reached the age of eighteen I hope he/she is ready to face the challenges of the world. Like the author, I went to a state university. Like the author, I emerged from it just fine and, in fact, stronger in my faith than when I started. God is at work just as much in the lives of students at State U as he is at a Christian university or a Christian home. God is at work in the lives of every one He loves and calls His own, all the time and in every place.

By the grace of God, I hope to prepare Caroline to face the world as a strong, Christian woman who is grounded in her faith and confident in God’s presence in her life before she was even knit together in my womb. I hope that God will use her to draw the lost to Him and that she will be an example of joy and love borne out of her faith in Christ. If she is only “good” because David and I expect it in our home, we will have failed her miserably. I pray for so much more for her than simply “being good” because she is in the safe environs of our family. I pray her security and passions will be based on her love of Christ and His amazing call on her life.