If I want to stop taking birth control is it okay to stop within the month, or should I finish the pack first?

Your choice. You can stop anytime you want, your cycle may take a month or so to settle back into a regular timing for your cycle but it won't cause any real problems. Remember, you will be able to conceive once you stop so you will need to use other protection to avoid pregnancy until you are ready.
Finish. First make sure that you are aware of the pre-conceptual advantages to Folic Acid supplementation if you are trying to get pregnant. Now is a good time for your yearly exam, identify any risk factors, and prepare for pregnancy. Once you have done the above, you can stop after your current pack to synchronize your endometrial lining. You can stop early, but this may lead to irregular bleeding.