What kind of preparation do I need before the recital?

Finish changing bow hair by 2 weeks prior to the recital. Also, prepare a set of spare strings that are ready to be used in case a string snaps during your performance.

It is not rare that strings snap during or right before a performance. This is due to various reasons, including a difference in humidity. In case of an emergency like this, have a spare set of comparatively new and well stretched strings in your instrument case in addition to a set of new strings.

I always change all the strings two weeks before the recital, use them for 3-4 days and then replace them all with new ones once more, so that I can bring a spare set of strings that are ready to go. You never know what will happen at the recital, so be as well prepared as possible.