Sending Mail...

I am planning on sending a letter from my school (Baylor U in Texas) in to my friend’s school (Bentley U in Massachusetts) and was hoping the letter would end up in her mailbox by around Dec 1 or 2 at the latest, but hopefully not much before Thanksgiving (so ideally like Nov 25-Dec 2). I know it takes some time for the college to process the mail and put it in the box and everything and also ship it out from my school, but roughly what are your thoughts as to when I should mail it? Her school’s mail department isn’t open on weekends.

Today? What’s the problem if it gets there early?