Shopping Cart: Am I ready for payment gateway?

I have a nicely working shopping cart system now. First off, thanks to those who helped me. And thanks to the Wappler team for forcing me to do this from scratch instead of a ready made extension.

Here is my cart site.

https://boxoffice.wlstudiotheatre.ca/

Have I done everything I need to do to move on to the next stage, payment gateway? Am I collecting all the important information I need? I hope I can do this next step. Get ready for lots of questions.