Hi Cara
That's no problem. Here's what to do.
First check that you have the private gallery 'ON'
Go to your manage store page>Look and Design>Look for private Gallery module and check it "on"
Be sure to hit save on the lower right of the page.
Now when you go to your store front you will see PRIVATE GALLERY listed on the side module and the clickable 'View my private cards' That will take you into your private gallery where your cards are.
Also you can click on the card from your private gallery and go to the bottom of the viewing page>SELL THIS CARD. Clicking on this will bring up code that you can paste into an email which will take your niece directly to the card for purchasing.
Hope this helps.
Pamela
I should have checked before I replied

I see you have your private gallery on and your cards are in there so hopefully the last part of my post is helpful