What distinction does Amal make between the two groups of women she and her Muslim friends call "part-timers" and those they refer to as "full-timers" (2)?

Amal states that she and her other Muslim friends use the term "full-timers" to refer to "girls who wear the hijab all the time, which basically means wearing it whenever you're in the presence of males who aren't immediate family" (2). She goes on to explain that young women such as herself are called "part-timers" (2). Amal says, "'Part-timers' like me wear the hijab as part of our uniform at an Islamic school or when we go to the mosque or maybe even when we're having a bad hair day" (2).