Hi Thank you for your question and welcome. My name is AJ and I will assist you. Legally she cannot take property that does not belong to her but if she is joint owner of the property she is entitled to enter it.
In theory if you do not agree to buy her out the property or pay her rent for her share of the property, she could go to court and get a court order forcing you to sell the home. What you need to do is gather as much evidence as you can to show your contributions and what share of the property you own.
I look forward to hearing from you. Kind regard AJ