That site's information may be technically correct but it's obviously incomplete, and it's even more obviously propaganda aimed at fresh, gullible high schoolers. They can crow all they want about how the "demanding exercise program will continue rain or shine, in extreme heat or bone-chilling cold", but it's immaterial because your PT will all be done indoors where it doesn't matter (except the 3-mile Pride Run, which absolutely will be cancelled for extreme weather). And it's hardly demanding.
http://www.navy-prt.com, while not an officially endorsed Navy page, has everything you need and more about PT scores.
EDIT: This is the link I meant to post. I was very confused when people were talking about the one above not including the 18-20 age group.
https://www.navycs.com/navy-fitness-assessment.html