Answer:
Most people think of menopause as the point at which a woman stops menstruating, but in fact, it is a process that usually takes years. Typically, women will have irregular menstrual periods for one to two years before stopping altogether, but menopausal symptoms can occur many years before or after that.
For women who have no uterus, or who have had surgical procedures to stop them from bleeding, menstrual periods will not be a clue as to where they are in the process. If you still have ovaries, you are susceptible to any of the other symptoms of menopause, which commonly include hot flashes, mood changes, decreased libido, vaginal dryness and sleep disturbance.
So, to answer your question of how you will know if you are in menopause, my answer is that if you are lucky, you won't, and you don't need to. On the other hand, if you are among the women who do have unpleasant menopausal symptoms, you can discuss treatment options with your doctor to improve your quality of life.