Although if you want to take advantage of Windows 8's advanced architecture, you might be better off getting version 11 or 12.
I have Premiere Elements 10, 11, and 12 installed on Windows 8.1 64 bit, and 10 and 11 work fine. Premiere Elements 12 works OK except for its issues of prolonged close times and prolonged time to open the choice of File Menu/New/Project.
Premiere Elements 12 on Windows 7 64 bit lacks these problems seen in Windows 8 or 8.1 64 bit.
You should do fine with your Premiere Elements 10 in Windows 8 64 bit. If you ever do decide you want to go to version 12, then definitely go the free tryout route before purchase. Since Premiere Elements 12 is the current version, Adobe offers only it for free tryout purposes.