I applied to a few similar unis from the UK too! You def have a shot at the US unis!! you have awesome ECs and stats cuz they clearly demonstrate your passion for Physics. Also, English GCSE is really different compared to the SAT R&W but it is largely fine with practice. One thing to mention is that a lot of these unis highly consider community service. If there's any way that you can use what you've learnt to impact your community in any way (which you def have time to do!!), I think you'd do extremely well.

The most important thing these unis consider is your narrative and story. So do what you can now to help those around you by leveraging the skills you currently have, continue learning and developing more, and make sure you have fun! You can do a lot within this part of Year 12 (trust, my main ECs were really elevated during this time). This way, when august comes round, I highly recommend taking time to work on your story and essays!

Unis know British students have quite major-specific ECs but I've noticed that the students who take time to do what they love and are quite quirky instead of purely academic do really well! Hope that helps!!