i know it's hard but you have to be firm. try telling her that she will never have friends stay over because they wont be able to stay in your bed.
Well she can if you let her, its up to you you can tell her to sleep in her own bed or allow her to stay in yours, you know its simply about choices.If you want her to sleep in her own bed tell her so and if she comes into yours send her to her own room but if you like the company and you want her there shes your daughter so its okay. Usually around this age they like to be getting some privacy anyway unless she has some anxiety .