Lack of timer

I just got a timer today but in the last couple days my plants have probably gotten 18 hours of sunlight and they are in in flower schedule. Is this going to hold me back much?

They will sense it a bit but if it was just the day you should be fine. I'm kinda in the same boat just the other way at the moment. I just got a timer but also put my girl into flower for a good 3 days LOL. Back to normal hours just stressed and moving slow

Flower time we always do 12/12 schedule , 18hrs a day probably too much love to plants, my atuos under the ts1000w light for was keep the good time, my girls look happy there