A good AP Biology course will have a lab component that would be difficult to replicate on your own, whereas AP Statistics or Computer Science is easier to self-teach. My eldest son earned a 5 on the AP exam without taking the course.[/quote] 
Definitely agree that the lab component would be an important consideration.  
However, depending on your kid, having a great teacher might be just as or more important. For my kids, having an awesome teacher would trump almost any other consideration, including subject matter (with a few exceptions).  It depends on what her schedule looks like tentatively for junior and senior year, but I would give serious weight to having an awesome teacher for stats and taking AP bio junior year.  I guess it would also depend on what other science classes are available-  I’m not sure I would take stats if it meant no science classes in her schedule that year. (Or course, ‘awesome teacher’ may mean different things to different folks too, so I would make sure you are on the same page there).  A great teacher is also often one who would write a strong letter of recommendation, which is something to weigh as well, though sophomore year might be a bit early to think about that.