If Serena is going, it will be this autumn.  The early signing period has now closed and universities cannot sign players again until April, so we won't see anything official before then in any event.

The application video does say for fall of 2016 and I assume that the Optimist is saying she can sign up from April still for the autumn. Therefore, that does look a strong possibility and I would certainly take it as quite likely that Serena is at the very least keeping her options open by not taking prize money.