The age of consent in Washington is sixteen-years old. This means, it is not illegal for a 24 year old to have sexual relations with a 17 or 16 year old. Of course, there are a few exceptions. If your boyfriend is a "supervisor" of you in some way; for example: he is your school teacher or your employer, he could have violated the law and should talk to an attorney right away. With the limited information I have from your email, both of you should not worry about any criminal legal consequences.