If it comes to fruition, the elderly will not go first. Presumably the distribution will follow the 2009 plan:
During the H1N1 influenza pandemic in 2009, ACIP developed a five-tiered priority list for vaccine distribution that frames the current discussion. First came critical health care and public health personnel, pharmacists, emergency responders, police and firefighters, along with "deployed personnel." The second tier included essential military support, the National Guard, intelligence services and other national security personnel as well as mortuary workers, and those in communications, IT and utilities. High-risk adults were in the fourth tier and healthy adults, aged 19 to 64 were in the last group. Children were a high priority in that plan, because H1N1 hit them harder. They will be a lower priority this time, Schaffner said, because they are not involved in current vaccine trials.
https://medicalxpress.com/news/2020-07-shot-coronavirus-vaccine.html