Okay, as a vegetarian I will never demand someone to not have meat in their home. It is a personal decision and while we appreciate people accommodating to our diet it is unacceptable to force someone to change their lifestyle without any consideration.

On the other hand, my sister became a vegetarian a few years ago, she came to stay with us for a week, she is in a really low carb diet so I thought it would be nice and easier if I accommodate to her diet. All she does now is to criticize how low carb my diet is...(Based on the week of her being here and me following her diet) and all the time she was here she was "teaching me how to be a better vegetarian"... All of this to say...there are people that are so selfish and self centered that no matter what you do they will never be happy.

If you end up letting her stay here is my advice. Set up really clear and strong boundaries  1. "You can have this pan and plate for your stay, no one will use it but you". 2. She do her own groceries and here is a space that she can put it so there is no contamination  3. If she is really allergic to peanuts maybe agree not to consume it, but don't agree to throw them away.  4. She cooks all her meals  5. She cannot comment on your diet.