is this right?

St
I had bought tickets to go see Panic! At The Disco in march with my boyfriend, we both are 18 and my mom and her boyfriend are taking us. We are intending on spending the night in a hotel but my mom is making it very adamant that she doesn't want me to share a bed with my boyfriend. I find this very unreasonable and I don't understand why she is doing this. She said it's very "unladylike" and apparently the other night we disrespected her because we kissed in front of her (in which it wasn't even in front of her we were in the car driving). She keeps asking me whether or not I had already had sex with him (in which I have multiple times and I'm very responsible) and I'm unsure if me telling her would change anything or make it worse. What should I do? 😔