My sister

My older sister is 16 and has a boyfriend. She's told my mam and dad that he's 17 I know he's really 20 my sister has threatened me if I tell me mam and dad his real age. My mam and dad are real strict and would go mental if they found out she lied. My mam and dad work all the time my sister and her boyfriend are always home and they go into my parents room to have sex on there bed. I told me sister it's disgusting because she doesn't even change the bedsheets after and she told me to shut up and says that I'm jealous. I want to tell my mam and dad this but I know my sister will say I'm lying and they always believe her and I get in trouble. My sister will then be horrible to me behind me mam and dads back when there workin. She always tells on me for the tinyest thing and she's seems to get away with everything it's not fair. What do I do? Ty Emma

Hi Emma, How old are you now? being the younger siblings or in between in the family has a role to do. Now your sister had this boyfriend always on your house while your mom and dad is at work. First, tell your sister to be a role model for you and do not teach you how to lie or something that can influence you in the future. Second, you have to do something about it, don't be scared of what will your sister do to you if you tell your mom and dad of what is happening there and the sex thing in their room. If you think your parents won't believe you then you should at least try. Nowadays camera's are very easy to access you know what I mean, it's everywhere, Android, Iphones, Ipad, digicam. Do what you have to do if your parents need evidence then give them. If things not on your side, go and tell your grandma grandpa.