On the point of rent - can't see how she would have to pay rent on a property that she half owns?
She only owns half the house, so she owes rent for the other half.
The options are
1) you sell the house and split the money
2) You sell half the house to her
3) you allow her to live in the house and pay you rent ( or cover all household expenses in lieu of rent)
If you and your sister disagree on which option is right, you can force a sale through a court order.
It sounds like she is your only living close relative, and she will be your sister for the rest of your life and you most likely do not want to cause a row, which is a good thing.
You and her need to sit down and draw up an agreement that she is renting the house from you, she pays the household expenses in lieu of rent and agree what happens in the future.
You still own half the house and have rights to decide what happens in the future.
What happens if she marries, or her boyfriend moves in ?
What happens if you lose your job and need the money ?
What happens if she moves out and rents it to her friends ?
What happens if she sublets a bedroom to someone ?
What happens if she is bad at getting things fixed and house is in bad condition ?
What happens if the roof needs to be replaced and she cant afford it ?
If you talk about things now, they are less likely to cause a row in the future, which is more important than whether you have to pay half the household charge.