Mate, don't stress, TSR is full of overachievers and people who want to do medicine. GYG posters are just people who want to well, so they're documenting their progress to maybe help them get advice from other posters and so they can see how they're improving over time. If you keep up with your work, study a moderate amount and seek help (from classmates, teachers or even here) if you do find yourself falling behind you should be fine