A Levels are difficult. Do not just choose them because it's the easiest option. You will have virtually no free time.
I'll put it this way, at GCSE I got 3A* and 8As and only worked for an hour or two each evening and maybe a couple at the weekend. Now, I work in all my frees, 3 hours each evening and all day both Saturday and Sunday. Oh, and did I mention that I'm still falling behind? At GCSE, you got a piece of homework to do from each subject once a week that would take you maybe an hour maximum. Now, I get work every lesson from all subjects, work emailed to me for the weekends and have to do 'consolidation' on a regular basis which then gets checked to see that I've done it.
Not easy, and not a small jump.