Firstly, that Busted obsession, don't be ashamed of it. There'll come a time in just over a decade when you'll be so glad you know every song word for word. Trust me.
Also those 'parachute' style trousers you insist on wearing, they're really not a good look. Neither are those weird netted vest tops you insist on wearing with them, but never mind, you'll learn. There's also the subject of that bad hair cut. It will grow. Eventually. So what it might have been right before school photos and yes, maybe it is still on display at your nan's, but trust me it does grow.
On a more serious note, it's ok to be shy, but try not to let it stop you from making new friends. Also you don't need to worry so much. That Christmas play? You're going to make an amazing snowflake and, believe it or not, you won't even be that nervous when it comes down to it.
Here comes the inevitable adult comment of 'your school years are the best of your life'. I'm sorry, but what everyone said was true. That's not to say you're not going to love being 18, or 20, but please, just enjoy yourself. Packed lunches, capri suns, fantastic English lessons and not quite so fantastic Maths lessons. You will miss it all. There's going to come a time when you'd do anything to turn back time, just a little bit.
Having said that, you can't. Don't get your hopes up. It's only been 11 years, society hasn't quite perfected time travel.