Okay I have a bigger sister who is like 18 now. She moved out when she hit 18 an moved in with my grandma. When she moved out I was happy. I mean I love her but she's not the brightest person. Well now my grandma can't take her no more and is about to kick her out. So she's going to move back in with us. All the rooms are took up already so she has to share a room with me. My room isn't the big its really tiny and has not a Computer 2 dressers a giant shelve and a huge queen bed. She's going to move her computer and all her stuff in here. I respect the fact that my parents love her and will let her move back in any time buttt... yeaaa... my sister has a tendencie to steal my stuff and trash my room. Me and my sister are the total opposite... she is trashy lazy and don't respect anyone.. I love being clean up and moving and I love respect... I don't know how I'm going to keep my stuff safe! How I'm going to keep my room clean! And how I'm going to be able to move or dance randomly in my room if she yells at me every 12 seconds for doing it. She can't even stand my friends. So I don't know what to do. I can't stand up to her because she's 18 and I'm 14 almost 15. I can't tell my parents because they know already. So its like UGHHHHH... What should I do to keep my room clean, my stuff safe, my friends not irritated, and me to be myself EHHHH...

You lock up your important "stuff," you divide the room (same as college roommates) into your half and her half. You try to respect her space by not dancing randomly when she's there.

What does you "love respect" mean?

I do notice there are other problems in your relationship with your parents, ranging from dating without their knowledge to wanting to get out from under their control. https://www.askmehelpdesk.com/high-school/high-school-freedom-608564.html

What is the situation?

You should try working things out with your sister, be patient with her, and tell her how you feel. You never know, things make work out in your favor. :)

She's your sister so she may understand if you explain. You parents can't force
You either so yeaaaa... just talk to your sister and sh may understand.
HOPE THIS HELPS!! >_<