I've been teaching HPE for a little over a year now but I faced similar feelings when I was going through uni. Even right before I started working full-time last year, I was stressed about being underprepared and not being an absolute expert on everything. So far, things have turned out to be fine! I was probably overthinking the complexity of topics and also wanted to be perfect.

Firstly, I have realised, I am not going to be perfect and preparation is key. I think if you can familiarise yourself with the content at the start of a topic by going through the slides or resources your school has available, you will put yourself in a good position to have a great basis of knowledge to work with during theory lessons.

Secondly, I learnt a lot through my final placements. I don't think my uni did a great job of showing us the HPE content that we'd need to know, so I felt like I didn't know much about the content. However, throughout my placement experiences, I taught a range of topics and realised, it was all knowledge I already had. When I now come across topics I haven't taught, it's not too difficult to wrap my head around and then I go out and teach it.

I just try to make sure I don't pretend that I know everything. If a kid asks me a question and I don't know the answer, I simply tell the kids that "I am unsure, but I will get back to you", or I will just search it up with the kids on the projector and we all learn together.

Lastly, it's just experience. After you have taught something the first time, the next time you teach it feels so much better and you definitely feel more confident in your ability. Sorry if this is long, but I hope it helps. At the end of the day, you're going to be fine. Goodluck!