Lil_Smoosh If you can open the game, you're running the 64-bit version. The minimum requirements posted in the EA App are sort of split between the games, so just ignore them.
Please try playing in a clean user folder. Move the entire Sims 3 folder out of Documents > Electronic Arts and onto your desktop. When you launch the game, a clean folder will spawn with no content. (Your saves and other content will be intact in the folder you've moved but temporarily unread by the game.) Don't add anything to the new folder yet; just start a new save, in Sunset Valley, and see how it runs.
If you get another crash, please list the full specs of your Mac: everything under About This Mac including the OS and except for the serial number. Please also list the free and total storage available.