@AmySims555 No, sorry, Sims 3 is 32-bit whether you install it from disc or Origin. So Catalina won't run it no matter what you do.
If you're really hoping to play Sims 3 and don't want to wait for the eventual 64-bit update, you do have a couple of options. One is to install Mojave (or earlier) on an external hard drive or USB and then boot into that when you want to play. You'd need at least temporary access to a Mac running Mojave or earlier, and of course the external storage.
The other option is to partition your hard drive and install Windows on one side. This is known as Bootcamping, and it's supported by macOS. You'd need enough free space for Windows and Sims 3, plus some extra left over in each OS, and you'd need to buy a Windows 10 product license sooner or later, although you could install without one and make sure the game works first.
If you'd like help with either of these options, let me know. Otherwise, the 64-bit version of Sims 3 will show up soon enough, and you won't have to take any extra steps to get it running on your Mac.
