That looks like building. Ovulation tends to be pretty conspicious, if you catch her ovulating you'll know without a doubt. The triangle back thing, for my female at least, happened throughout the process. There's a pre-ov shed, almost always. The pre-lay shed is less dependable but from my experience, most females have a pre-lay shed.

If your girl fasts during the breeding season (which mine usually do) there probably wont be many sheds other than the pre-ovy and pre-lay sheds, since she wont be doing much growing and is dedicating all of her metabolic resources to making those eggs.

Good luck!