Peri-menopause, the changes your body is going through to get to menopause, can last up to 12-13 years. You can have all or none of the noticeable symptoms for a short time or a long time. Changes in your cycle is definitely an indication you are there, but it's anyone's guess how long or what will happen next. In your late 40s I would agree that you are going thru peri, but for how long...???

My mom stopped at 49 with no symptoms. I stopped at 54 after a few years of severe mood swings, hot flashes and a semi-regular cycle.

BTW, menopause can also affect you mentally, not necessarily MI, but memory and recall and other ways.