There is a gender gap in physics uptake in schools, and it is something you need to be mindful of.
Keep a mental note of the language you use and ensure that your time is equally distributed throughout the class.
Are you visiting the girls as much as the boys? If you have a friendly colleague available before your observation, you could ask them to watch you teach for a fixed time and keep a tally on how much time you spend with different students in your class. The results may surprise you.