Would also point out here that there's no set guideline as to how long you should be spending. If you're using that time well to learn, then that's fine.
Questions like this and others e.g. "how many practice exams should I do" is subjective. There isn't a fixed number and quality definitely over quantity here. Some could spend 1 hour doing textbook questions and just get it, while others may take more time. I don't think it's necessarily a bad thing to spend longer and you definitely shouldn't feel bad - you could be analysing questions more in-depth and understanding, as opposed to skimming and rushing.
Just like I posted in another thread... we aren't programmed the same and really if you feel that it's too long, ask yourself if you could be spending your time somewhere else which would be of greater benefit. Speaking to your teacher too, who knows you well, can help provide different options tailored to you that will still get you results.