From what I've researched Civil Twilight provides enough lux for plants to sense light, does that mean I'm getting about 13 hours and 27 minutes of daylight?
yes your right. if you want total darkness right now you would either cover your plant form the extra light or put it indoors. the light will change later this month and your plant(s)
will then trigger to go to flower. by having the 13h 27min going the plant will grow and continue to veg until the 12/12 cycle and the plant will transition into flower
hope that confirms what you know