you can do whatever you want, but it may not supply desirable results....
If you want to do the math you may be able to determine the right amount of unfermented juice or wort you need to end up without a) a bottle bomb or b) uncarbed product.
but if you are just getting into this, maybe try to keep it simple and focus on sanitation and process before making it complicated for yourself.
Just my $.02 YRMV
BTW, you do mean carbonating...right?