Purchases don't ask for credit card expiry date

Site URL: http://www.kidspaceprograming.com

Hello! When a customer is making a purchase from my site and entering their credit card information in, the only have to enter the number and code. They are not asked for their expiry date. some of my customers are older and have had an issue trusting this. I've contacted Stripe and they said its not on their end, it has something to do with squarespace. Can anyone help me clear up this issue please? 

sure, they're asked for the card's expiry date. here's a screenshot of my store's checkout page. i highlighted where customers must enter their card's expiry date.

i went to your site and added a product to the cart. here's a screenshot with the field for putting in the expiry date shown. so it's clearly there.