Start with 6 strings, not 12. Go play some acoustics and see what fits your body shape. Smallest are called parlor guitars, largest are dreadnoughts. They sound very different, so finding the right guitar for you is more about the sound you want than the size. Plenty of pro female players of small stature rock full size guitars, so the size issue for playing isn’t such a huge deal. Of course, smaller guitars are easier to hold, so the ergonomics is something you would have to decide about.

For looking at acoustics, try to get something made with a solid wood if you can manage the price. I would also be cautious of really cheap acoustics, as spending a bit more money on a decent one will save you a lot of frustration in the long run.