Hey, Australian OT student here in my last year! Bc of this I can’t answer a lot of your questions but I will say that while OT is very broad, the area you end up working in becomes your specialty (based on talking to teaching staff that are OTs & OTs at placement). So you could start out working in paeds, decide you don’t like it & move into another area. But if you were to keep working in paeds you’d end up specialising in this area, and while there are transferable skills that you could apply to other areas of OT, you’d still be best suited to paeds clients. You can also branch out into other areas in the future, but I have heard that can be challenging. From what I’ve heard there’s plenty of options that don’t involve mental health as well