my brothers girlfriend always wearing my clothes

dont get me wrong i didnt have a problem with it at first because she was asking and letting me know what she was taking hut it started to get to the point where she goes in my room n just takes stuff.. like just now she came up here n start talking to me then wen to my black bag n start going thru it and was saying how i had alot of clothes n she done took my white silk bra and a little pile of clothes😭 she played it off at first wit my bra like “oh i cant fit this” then tried it on n was like “oh i can even with my shirt” n i gave a hint i said “yeah i dont have alot of bras” n took it wen she went down didnt ask if i needed it or nothing. i be wanting to tell her but would it be disrespectful? bc i tried to come up with the nicest possible way to say it but it just doesn’t work lmao i live with them but i feel like just because im staying in yall house doesn’t give her the right to just go in my room and take my stuff lol. like literally as im writing this she came up n asked me how much does the jel i use cost cus shes always been using my jels lol and i dont be having the money for be getting jel like that cus my hair is so hard to deal with like I NEED jel. shes been using that too🤦🏽‍♀️ she dont ask or anything. i dont wanna make a big deal out of all this. but a few days ago she got on my case bc i let my boyfriend stay a few more hours in the house while i was at school n she got mad bc he was pose to leave in the morning but he was gonna leave wen i got home from school.. saying how i needed to respect they rules n stuff but you want respect but wheres mines ? you know? lol like i dont mind her wearing my stuff i just want her to ask and put it back 😂 and as for jel i dont want her using it fr bc she use to act that way towards me about hers before. like she let me use it but deep down inside you can tell she didnt want me too. but anyway.. how should i put it without trynna sound like im starting something?