They won't kick you out for an incorrect citation, especially since it's your first infraction. They'll probably just deduct some marks from your paper.
She has to formally report as per the school's academic integrity policy, but that doesn't mean the punishment will be severe.
They only kick people out for repeated intentional plagiarism. For example, if you're caught copying and pasting from the internet twice, they might kick you out. Or, if you paid someone to write a paper for you and submitted it as your own/if you copied a paper from the internet, they might kick you out without a second chance for that.
Incorrect citations aren't such a big deal. It's obvious that there was no intent to plagiarize, and that counts for a lot. They have to punish you in some way since it is a rule infraction, but I think it will be mild.
Ward Churchill anyone?