Y13--Is it too late to get the grades for med?

In a year is it possible for me to change my grades-I am going to be going into y13 after the hols-and i need to majorly increase my grades in my a-levels, i took chem,bio & eng lit..i do aqa...by change i mean improve largely...i cant help but feel like even if i put a lot of effort in now i left it too late

Instead of asking if it's possible, actually start making a change right now. Study over your holidays to go over the stuff you didn't understand in first y12. review your study habits to see what's working for you and what isn't. Don't just read through your notes and highlight, look on the internet for more effective study techniques and try them to see if they work for you. When you get into y13, you won't have time to be trying to learn all the y12 content that you didn't understand at the time. You have about a month before start of next term, which can be a lot of time to get stuff done. Start off by organising all of your folders and work from last year and then actually review it all. Study for it all now and you will be able to relax in your holiday next year after you've finished your a levels. You can even review topics that will come up in the future to get yourself ready when you cover it in class. If you actually want to improve your grades, it IS possible - just start now and consistently maintain a good routine and continue to study until the end of your exams. Good luck.