It is quite difficult to tell from a pic, just how close a fish might be to giving birth. Some fish don't like being confined in the breeding net or box, as they don't provide much swimming room, so depending what method you use, leaving her to the last minute, more or less, may be less stress on her.
If you can provide another tank, and furnish it with mosses or breeding grass, then you can leave her in that and not worry when the fry are born, as most of them will be able to hide and not be eaten. Once you see she has given birth you remove her.
If you can't do another tank, then get the largest breeding net or breeding box you can find, or that will fit on your tank, and keep an eye on her. The signs you have been told about are the only ones anyone knows, except by experience with a given fish, so you have as good a chance as anyone to tell when it might be close to the time, and put her in the net then.
Good luck. And if you don't have too much success this time, don't worry too much. You'll get another chance, as she is very likely to get pregnant again, unless you do not have any male fish for her to mate with.