I am at least 12 days late, but i have irregular periods. my mom says wait until the end of the month, should i take a pregnancy test or should i wait?

I'm with Mom: If periods are randomly irregular, a woman isn't "late" because she doesn't know when her period is due. Without a period due date, she can't say she is late. However, if her irregularity stays within a narrow range, such as getting periods 4-7 weeks apart, she could say she is "late" if it has been more than 8 weeks since her last period. If worried, test now. Otherwise, Mom's advice sounds fine.