As soon as I'm done creating the character, I go officially into the gameplay world and my FPS becomes 30 when it should be 60, making it lag ridiculously, especially for a game like this.

Have you messed with your settings all I can really think of to solve it

PCSX2 unfortunately isn't a great emulator. Very few games on it run perfectly, and that game isn't one of them.

Well is there a different one I could use? I haven't messed with the settings. I just installed it and opened it up right away. But then again i could try Gamecube emulator since same version of Sims is on that one.

There isn’t another PS2 emulator that I know of (if there is, it’s probably even worse than PCSX2). Emulating the GC version with Dolphin might be a better option as Dolphin is a solid emulator.