Certainly you could wait until you were 18. In fact, the Washington Legislature just amended the law to allow prosecution to start any time before you turn 30.
But your decision to wait could reduce your credibility, especially because you intend to wait for financial reasons. In other words, you might be less likely to be believed if you wait. I suggest you consult with a lawyer before you decide to wait; you should be able to tell the lawyer the whole story without losing control over whether a report gets made.