No, it is partially true. Endometriosis is mostly found in premenopausal women aged around 25-35 years. However, women as young as 11 years old have also been reported with Endometriosis; however such cases are too less. Normally after menopause, chances of endometriosis lessens due to decreasing size of endometrial implants. But, some women may get endometriosis after menopause as well - hardly 1% of all cases.