You can sue, but there are problems since a 14 year old probably doesn't have extraordinary assets and her parents' insurance company would probably deny coverage. The parents would probably only be liable for a very limited amount of money because of their daughter's misconduct. "The parental immunity doctrine does not apply where injury to a child results from a parent's or guardian's willful or wanton misconduct." Zellmer v. Zellmer, 132 Wn. App. 674 (2006).
Further, RCW 4.24.190 (...
The law allows and requires full compensation for all injuries caused by the negligence of another. That includes medical expenses, lost wages, property damage, and (last but not least) reasonable compensation for the pain, suffering, emotional distress, mental anguish, etc. the injured person suffered.
Your insurance company will defend you because the impact was between your nose and the other guy's tail. If your insurance company doesn't settle, you get to the part later where everybody calls each other liars.
Something you should probably discuss with your lawyer is the possibility of offering to exchange a covenant not to execute on a judgment over the policy limits for an assignment of the at-fault party's cause of action against his insurance company for bad faith in the insurance business. If the action for bad faith in the insurance business goes well, it can be worth much more than the policy limits. Attorney's fees may also be recoverable pursuant to OLYMPIC STEAMSHIP v. CENTENNIAL INS.,...
You may have been a victim of the crime of cyberstalking. RCW 9A.61.260. (http://apps.leg.wa.gov/rcw/default.aspx?cite=9.61.260). If so, you should call the police.
There may also be a cause of action at civil law, but at civil law you would have the burden of proving by a preponderance of the evidence every element of your allegations, including the extent of the damages. Perhaps some attorney in the category of "personal injury" would be interested.
When one party to a contract attempts to unilaterally change the terms of the contract, the attempted change would be void. Contracts have to represent a meeting of the minds, an agreement, a bargained-for exchange reached at arm's length on a level playing field. Your statement indicates circumstances where you might have a counterclaim for breach of contract.