NAH yet, you both understandably are upset. You're upset because you're trying to something positive for your new family. She's upset because she's going through a lot of change and hasn't had much of a say. You are never going to win in a war with your gf's daughter, because your gf will (understandably) put her daughter's interests first.

This situation needs to be addressed with communication, not with pressure and force. Coronado is really, really nice and she'll love it, but she needs to feel like she's part of the conversation. Have you sat down to have a family conversation with them? Have you talked with the daughter about her feelings?