The onset of menopause varies greatly between persons. The average age of the last monthly period is at age 51. But the monthly periods don’t just suddenly stop. Instead, the onset of menopause is a gradual process, which takes from one to several years.
This means that if the average age of the last period is 51, the first signs of menopause start one to a few years earlier. From this fact alone, we may conclude that your age of 47 is within the normal range.
In fact, any age between 40 and 61 is considered as normal for the onset of menopause, though the extremes of this range (40 and 61) occur far less frequently than the average (51). Still, you are well within this natural variability.
If you smoke, or have smoked for a number of years, then menopause starts earlier. But even if you never smoked nor ever inhaled smoke, you have absolutely nothing to worry about.