Perimenopause or “second puberty” is the two to ten years before the final period. It’s different from menopause, which is the life phase that begins one year after the final period. If you experience symptoms (and not everyone does), they’re most likely to occur mostly during perimenopause and are temporary.
Because you could have your final period (menopause) anywhere from age 45 to 55, you could start having perimenopause symptoms as young as your late 30s, but more likely your mid-40s. So, if you were born before 1986, you could be in the territory of perimenopause and yet still be relatively young. That’s why perimenopause is not about aging. Instead, it’s an important (and unavoidable) recalibration of your hormonal system.