Is having a prolonged period sign of the change I have been told I'm starting with the change by a doctor

Hi ellie1824... welcome to AMHD,

Changes in menstrual cycles, including prolonged bleeding, can be possible signs of perimenopause.

However, it would be wise for your doctor to do some checking on other possibilities first... if they haven't already. There are a number of possible causes, such as polyps, that can also result in irregular bleeding.