I may be the lone voice of dissent but at five years old she should have a proper whitewater PFD that fits correctly without a crotch strap. We started with something similar to those when they were 1.5 and 2.5 when they started rafting class 1 and easy class 2. By 3.5 yrs old I had my youngest in the NRS Youth PFD. I tested it extensively to make sure I could grab her by one shoulder strap and haul her in easily.
The pfds with the large wings around the head may be useful if they are completely unconscious and floating out of a Class 4 rapid. I have found that most kids hate them and they ride up into their crotch strap because they don't have the adjustments over the top of shoulders and the appropriate side adjustments to actually get a good fit. I also think it is good practice for later boating to have something that is actually snug around their body so they can practice active swimming, not passive floating. Your Kids May Vary.
On a side note. I contacted our local pool and got permission during a slow time to do throw bag practice in one end of the pool away. Made sure mine knew how to grab and roll to their back and not ever wrap the line around their hands.
Not faulting you on wanting a crotch strap as that would seem to be the 'safer' call, but I don't like these ill-fitting behemoths at all. These pics are at 3.5 yrs old ( rowing) and 4.5 (sleeping). Every time we boated I would check the adjustment for the clothing of the day. And actually pick them up with it to make sure it wouldn't come off. She is 10 now and still wearing the same PFD. She will be ready for something else in a year or two. My oldest who is 13 has outgrown hers this year finally. With all the adjustments we just kept moving it out.