Generally, if you want to attend pharmacy school right after graduating with your Bachelors, it'd probably be at the end of your junior year. That way, you can apply during your senior year and matriculate the following year.
It really depends where you are applying. Some schools require less pre-pharmacy coursework for admissions, and you necessarily do not need a Bachelors. The school I applied to you can complete the pre-pharmacy coursework at the end of Sophmore year, so people usually take the PCAT in June/October leading into their Sophmore year.