I know theres a 12h grace period where a bc pill isnt considered missed. is it the same with taking it 12h earlier?

Oral bcp use: The most important part of taking today's "low dose oral contraceptives" is to keep the interval between "active" (those containing hormones) pills at most 25-26 hours, as longer intervals (12-24 hours or more) will not usually affect pregnancy occurrence, but may originate bleeding from withdrawal. Do not let more than 7 days of placebos elapse w/o starting a new pack of "active" pills.

Some basics: The pill provides your bloodstream a level of hormones meant to keep your body from releasing an egg. For this to happen, a relatively constant level of that hormone(s) is needed. Taking a pill too soon, skipping, or too late can allow the level to fall to a point where you release an egg & risk pregnancy. It is beast never voluntarily change the pattern. If it happens use backup BC for a month.