Eye dominance is a beautiful thing, isn't it? Cross-dominance can be a pain in the arse. If you are either left-handed but right-eyed or right-handed but left-eyed, you're cross-dominant.
I'm cross-dominant, right-hand left-eye. We found out about mine when I was 7 years old and first learning to shoot. Since then, I have shot longguns left-handed, and all of my rifle and shotgun purchases center around that fact. Handguns are less of a big deal, though I find that it isn't as awkward to shoot handguns ambidextrously.
There are several ways to test eye dominance, and I'll bet you'll find yourself to be left-eye dominant.
Keep both eyes open and make a thumbs-up at arms length and make your thumb cover up something on the wall, like a light switch. Now close one eye. Is the switch still covered? Open that eye and close the other. Did your thumb move? Which eye was closed when your thumb moved? That is probably your dominant eye.
Another way is to make a circle that you can see through with your hand. Look at something through that circle. Now, close one eye, then the other. Whichever eye you have to keep open to keep the object centered in the circle without moving your hand is your dominant eye.
If neither of those makes sense, maybe someone else can explain it better.
