You have some great plans! I would first start off by thinking about if you want that to be your career or your passion. There are many ways to do those things that aren't a 9-5. You could volunteer or do part time work. Next, connect with your local or home church and express your interest to them. You can see if you could shadow the current youth pastor. Then, get to know the Bible from front to back. Before you can teach kids about Jesus, you need to make sure that you know everything about him first. If you are in college, take some classes. If you are in high school, join your Bible Study and Sunday School Group.