Speak to your local council or volunteer bureau and tell them you'd like to become a youth leader and would like to get some experience. They'll put you in touch with a group (or groups) who will welcome some volunteer input. When you're a little more experienced, you can go for a part-time youth worker post and then onto something more.
I used to be a youth leader in the 1990s, at a school for with kids with learning disabilities. One lad was desperate to attend but he was too young, so his dad came along to take responsibility for him. Dad helped out as a volunteer in all the activities we did and eventually became a paid worker, not the least because the kids adored him and would listen to him when all other reasoning failed with them. After the school closed, he moved on and opened a youth club via his church, which is still going strong with dad at the helm, plus he's now working with young offenders teaching them woodwork skills. Considering this dad also went to a special school in his youth, he's a fantastic role model.
So never underestimate the power of volunteering.