With respect to whether a victim has to testify that all depends on whether the offense can be established without their testimony--sometimes it can and sometimes it cannot--it is totally dependent upon the facts of the particular case.

Neither the parents nor the child decides whether to file charges and pursue a prosecution--that is a decision for the local prosecutor although he/she may abide by the parents/child's wishes.

Almost all crimes have a statute of limitations--they may be extended or tolled when the offense is alleged to have been perpetrated upon a minor.