I don't think 39 is too young. Perimenopause can last up to ten years. The definition of officially entering menopause is not having your period for one year. I'm 48 and going on about 7 months of no period, with occasional hot flashes. I hope this is it (for periods).

Since you posted this under the "Coping With Emotions" section, do you wonder if you're in perimenopause because your emotions are all over the place? I've definitely noticed a worsening of my moods over the past couple of years. Right now I'm in a bipolar depression, and I haven't been in one of those in about 15 years or so!