There are three real scenarios in this situation:
1. She gets with you, and her father disowns her.
Pros: You guys are together.
Cons: She loses her father.
2.She doest get with you but you guys stay friends.
Pros: She doesnt lose her father, you guys still are in contact.
Cons: You guys are not together.
3. She gets with you but keeps it a secret from her father.
Pros: You guys are together.
Cons: You must keep your relationship a secret, and she has to lie to her Father.
My Advice: AT ALL COSTS AVOIN #3. IT IS NOT WORTH IT TRUST ME. #1 Is not worth it either, in the case that you guys dont happen to work out in the long run, she will have no one, and if you really love her you dont want that to happen. Keep in mind sometimes people may be in love with eachtoher but they still wont work out because outside factors keep them from maintaining a healthy relationship, and Im not talking about her father. #2 is best solution. For now be her friend, and work to prove to her father that you really do love his girl. A father will never think that a guy is worthy enough for his little princess, so the only thing you can and should do is that at the very least you will take care of his daughter and make her happy.