Before you get too excited, check your computer.
If you have a modern PC but a 2015 project file, you don't need the old software. Just install the new Premiere Pro—it automatically converts legacy files. adobe premiere pro cc 2015 download
You cannot buy a new subscription just for CC 2015. You must have a current Creative Cloud plan. Before you get too excited, check your computer
This era of Premiere Pro was focused on bridge-building between casual and professional editing: Adobe Premiere Pro CC 2015 Review - Videomaker Before you get too excited
No legitimate website offers a standalone "free" full version of Adobe Premiere Pro CC 2015. If a site claims otherwise, you are about to install malware disguised as editing software.