... wellll, technically one can clone an auto, though not all strains, photo or auto, take to it well,... the deal with auto's is, the cells have their own internal "clock", and they know how old they are regardless of being still part of the plant, or as a cutting,... so even if they have sufficient time to root before bloom triggers (it may delay some, but never indefinitely like a true photo'), they won't do much veg-wise meantime,... there's no work-around for this with that auto gene expressing itself!
If you have a plant that's well past the time it should have started bloom, then you might have a mis-fire auto, or a seed mix-up at the breeders end, bad genetics, etc.,... from what I've seen, best thing to do is treat her like a photo' plant, start 12/12, maybe slapp some high P-K nutes in there as well,... in any case, taking clones will be a fun experiment to see, so why not?