Female run time is longer
Males are required to complete the run in less than 12:30. Females have a minute longer. Remember, this is the established standard. Commanders can waiver or request a waiver from a higher authority if an applicant does not meet any IST requirement before ship day. At this point (getting a waiver) you are a marked man/woman. Folks at MCRD will be paying particularly close attention to your IST and physical progress.
My recommendation is to practice for the real thing. Find a stretch of road and mark out 1.5 miles. Run that route every other day, as fast as you can. On the days in between, run three, .25 mile segments as fast as you can. Run the segments with at least a ten minute break in between. Hill work and windsprints will help you too.