Hi. I know I'm a year late to this but I have good advice for this question for anyone.
Personally, in year 9 and 10 I really didn't work too hard and basically done the minimum of going to school and then completing homework, I rarely did revision and I was getting around 4's and 5's. When covid hit last March and we went into the first lockdown, I changed as the homeschooling was suitable for me and I suddenly done better in exams and in lessons, I also became more confident as a person. Because of the lockdowns, I got more motivated to revise and work harder in my subjects and then my results went up to 7's and 8's, only in the space of a couple of months. So, it is possible to just try in Year 11 but if you want to do this then there has to be a big commitment from you.