I don't have a proper title lol

My bf and I have been dating for a while, since April, we're the same age but he's alot more mature than other guys that I've had experience with involving my period. I've never spent the night with anyone in my period before and he suggests that I do come over and stay the night anyways. We are supposed to be getting an apartment together and I know that it's gonna have to happen sooner or later so I said yes and when I started on Monday I told him not the first night because it's always super messy. He said it was fine but I told him that I'd cry of embarrassment if I made a mess so he suggested the third day, which is today. TONIGHT. I'm nervous what do I do? how do I prepare for this? What if things go wrong. He says it'll be fine but I'm still worried.