She's not even old enough to get a driver's license! Isn't the commitment she is expected to make by being baptized a LOT more serious? Let her know that if she wants to be baptized, that's fine, but she needs to be grown up before she can make that decision. By all means, talk to your attorney, and make it clear that, as a minor, she should not be subject to WT "discipline" at the level of an adult. If she does get baptized, her dad and the elders should sign a statement giving her some latitude to make her own mistakes without being shunned.
The other side to this is that she could get DF'd as a teenager, and her dad might not speak to her. Then you would have a golden opportunity to keep her away from the KH. I would tell the attorney she can't go because she's on their "bad list" and no one would be allowed to speak to her, and that's too harsh for a person her age.
Good luck with this situation.