18 and 17 year old dating
The number 1 priority you have to worry about is your relationship with her.
While this situation makes things not as you want them right now, a poor relationship with her at 17 can be devastating.
These are all valid questions and make the situation difficult to handle.
You allowed her to create a relationship with this boy and now you need to respect that relationship.
If you do not, she is going to learn that you don't respect her feelings - they don't matter to you, she has to fight you to get what she wants and that love is hurtful. I don't think she is just saying she hates you or that she thinks you hate her, she is most likely feeling a little bit of it.
It is a tricky situation, a hard decision and one that can cause arguments within the family.
When your teenage daughter has an interest in a boy who is older than her, it is easy to become concerned.