Because of the science behind scratch baking, I'm not sure how successful you would be cutting a recipe down in size. A doctored box mix recipe would be much more successful.
What I've done in the past when I didn't need to bake so many cupcakes was either bake them all and then freeze the ones I didn't need in ziplock bags. I would defrost them, out of the bag, when I needed them and they were just fine. Or you can freeze the left over batter and then scoop it frozen into the cupcake pan when you're ready. There are threads on freezing batters. Some people will thaw the batter some don't. I partially thawed it so I could get the scoop into it. They worked well and tasted the same as if I'd made the batter that same day.
If all your ingredients can be easily halved, there should be no problem. Write it out first, don't calculate in your head - that's how mistakes happen... When a product sinks in the middle, it's often from underbaking.
Or just plug it into a calculator:
If you convert to weight it is easier, convert to grams and you can do any amount.
Does the baking time change if you halve the recipe?
I convert my ingredients to ounces or grams and have easily and successfully cut my recipes. I had a recipe for 24 cupcakes, and I cut it down to 3 cupcakes. They were delicious! I didn't adjust the baking time but you should watch them just in case.