Is my period early because my sister started hers?!
Question: Is my period early because my sister started hers?
Answers:
Actually research suggests that female relatives or close friends living together often end up synchronising periods. However, this usually only happens if they've been living together for a long period of time, so while this may be it, it may just be a random thing. Periods can be so unpredictable at times eh? haha.
Psychology student
Yes it is possible. Sometimes if there is more than one female in a household their periods will start around the same time. Its a little weird but it happens in my house too.
http://thelittlepinkbook.webs.com/
Advice website for teen girls
Yes, that is possible. I have been late before, because my mother was starting menopause.