Depends on which tyoe you go into. Childcare in hospitals, like paediatrics, is well paid. Baby sitting on the other depends on how well known you are and how well you do, people telling their friends about you if you're really good at it. There's also teaching which falls under children education, not sure if it's childcare, and also social workers caring for orphaned children (the pay isn't good here either)
It's a wide variety
Maybe focus on the closest hurdle right now and go from there. Like choosing gcses. Your views and interests may change. Alevels are more important than gcses so just take it easy for now.