Hi Natasha,
Your listing is probably set to "Instant Book" which is why she was able to book without you approving (Either that, or you pre-approved her booking).
I understand that it can be frustruating to risk your Superhost status in this case. So I strongly recommend that you report the case to Airbnb immediately.
During my last Airbnb Meetup - the Airbnb explained that for certain cases like these, Airbnb can cancel a reservation without you losing your Superhost Status.
If you personally cancel the request on your own, without Airbnb - there is nothing that can be done about it. So I recommend that you inform Airbnb immediately.
Hope this helps!