Auto or photoperiod

Wait a week or two, and if it starts to flower, it’s definitely a photoperiod strain. If not, it’s an autoflowering strain. Sometimes autoflower strains take longer than others; I once had an autoflowering strain that grew just as as a photoperiod one but on 20/4 light cycle. You never know how long it will take for a autoflower to start flowering

if it's a photoperiod, 1 day isn't enough... you'll need to maintain 12 hours of uninterrupted darkness each day (one way or another) until it finishes. Some autos do vege longer... probably safer to give it more time to know for certain in the future. But, changing a photoperiod from long dark and short dark can also fuck up the plant. At this point, you may just want to assume it's a photoperiod, if you already gave it a long dark cycle. If you can run the same DLI as you normally would for the autoflower light cycle over 12 hours of light, the yield will not suffer.

Yup. just put her in the dark for a day. Some auto's take a little longer tho - mostly the point when they reach flower sate is when the roots hit the bottom and side of the pot.