There is quite a big jump between GCSEs and A levels. It depends on the subject of course but in general, A levels require alot more revision and hard work. Don't be afraid of them though If you choose subjects you enjoy, it doesn't feel so bad. The years go quickly too so it'll be over in no time. Hope that helps, good luck in the new year
Do things you enjoy and you'll be fine. Make sure you remember that it is a big change and a different style of learning from GCSEs, and don't underestimate how fast the year goes! It'll be over and exam time before you think you've had a month there... That was the scariest bit for me.