Are you treating your child's prayer for salvation and baptism like some parents in other traditions treat Confirmation?
Not being in a tradition that offers Confirmation, it baffles me why so many parents make such a big deal about their kids making it through Confirmation without equally making it a big deal that they make it through high school and college walking strong in their faith. It's easy to notice and criticize something that's not part of your own tradition. But how many parents in our tradition make a big deal about their kids praying to receive Christ and put a lot less emphasis on making sure they are cultivating and growing in that relationship all the way through school and college? Or making sure that the prayer was legit? I don't know, but it occurred to me how silly it must look to those outside of our tradition to put absolute trust in something that could easily be done out of peer pressure, desire to please their parents or just plain ignorance.
I received Christ when I was eight years old and I remember the time well. I'm confident that when I prayed to receive Christ, it was a prayer of genuine faith and I started a new relationship with Christ that day. I don't remember the exact moment I prayed, but the moment I do remember was the conversation I had the next day with an older, close friend of mine and telling him that I had accepted Christ and that I could no longer participate in some things we were doing that were wrong. It changed the nature of that relationship. So I'm a big believer in giving kids an opportunity early in life to receive Christ.
But let's not ever trust a prayer prayed out loud any more than a class completed in eighth or ninth grade when it comes to the faith and the eternal life our our kids. I'm not advocating praying repeatedly to receive Christ or living with a lack of assurance of salvation (or cultivating lack of assurance in our kids). But let's also remember that saving faith is evidenced in life or it's not saving faith. And as is even the case with adults, a "first-time decision" is sometimes a false start, for some it can be a first step in coming to faith and for many it's the real deal. (That's why I never refer to first-time decisions as anything more than as a "first-time decision.")
What I am saying is that when your child prays to receive Christ, most of the work of spiritual guidance is still ahead of you. And that work doesn't end at any grade level. In my mind the rule is that as long as you can require that they go to school, you require that they go to church (more importantly, youth group). Exceptions only prove this rule.
And while we're at this, there is one very clear exception: requiring church when you're not committed yourself to serving God and growing in your faith is a farce. In fact, do your kids a favor. If you're not walking with Christ, please DON'T require them to go to church. But it's never too late to repent, to start pursuing that relationship and to model faith for your kids.