Welcome to HCM,
You are 39 years of age and detected to have enlarged uterus
There are many causes of enlargement of uterus common one are large uterine leiomyoma(Fibroids),adenomyosis
,any other cause like infection, or malignancy.Pelvic congestion syndrome
Please go for Gynecological check up to find out the cause so that it can be treated .
Hope there should not be anything serious nature.