There will be public celebrations for the commoners, followed by a grand gala for the nobility. As Queen, you would be expected to lead the procession and take part in the ceremonial planting, possibly give a speech. However, since you are not yet crowned, it is not required, and it may not be safe to expose you to the public.
What do you mean, not safe?
Outside of the castle, you are less well protected. If anyone means you harm... Think on it now, decide later.