Saying Ma'ariv at Plag HaMincha

You may say ma'ariv on Friday afternoon (erev Shabbat) as early as plag ha'mincha (1 1/4 halachic hours before sunset), as long as you say mincha before saying ma'ariv. So, if it is now plag ha'mincha, you may say mincha and then follow it as soon as you wish with ma'ariv.
NoteOn erev Shabbat, you do not need to say mincha before plag ha'mincha in order to say ma'ariv before sunset. This is unlike on weekdays, when you must say mincha before plag in order to say ma'ariv before sunset.