About the same. We talk about our doctrinal positions and which ones are non-negotiable: inerrancy of Scripture, creation as told in genesis 1-2, virgin birth, sinless life, substtitutionary death, physical literal resurrection 2nd coming. By the way, we don't insist on such issues as Calvinism and pre-mill, pretrib. We talk with them about the responsibilities of a church member such as attendance, giving and ministry as well as contributing to the fellowship of the church. And then we vote on it. Because we do that, we now have very few inactive members.
The youngest I've ever baptized were six years old. And, I'll have to say that I was very careful. But, I did find that these few children had more knowledge and understanding than some of my long term church members seem to have when it comes to knowing Jesus. So, I don't think it so much of age as it is demonstrating a spiritual awareness and understanding of what it means to become a follower of Jesus Christ.