Anna, congratulations on your first sale!
What do you mean with 'the order is still open'?
Your shop shows one sold listing.
Do you mean you haven't got paid yet?
The only payment option I see in your listings is 'other'. So, how do you plan to get paid? Did you contact your customer about it?
Is there a reason you are not accepting the usual payment methods, like PayPal (the best and most secure option) or Etsy's Direct Checkout (of which I am not a fan, but it is used by a lot of sellers)?
Make sure you get your payment before you send out the package!