Sorry that I am only just catching up on the latest news on the site and so didn´t welcome you earlier. Anyway, hope things are sinking in a bit now and that you are being well looked after.
Keep calm about the transplant (easier said than done I know). As others have said not pleasant but mostly it´s just tiring and you will be very well looked at.
You are so young to get this that I really feel for you – but at least being so young you probably will cope with the physical effects of the treatment – hope so anyway!
Try to keep positive and keep doing the things that have always given you pleasure in the past or even try doing a new hobby. If you can keep active before the transplant it will make recovery much quicker I think.
Anyway, my thoughts are with you and hoping that things go well.