Re: will the Sims 4 run on my MacBook Air?

It should run ok and you have plenty of RAM. But and there is a "but" please note the following.

1) You should not run on Ultra High graphic settings as this can damage your Mac in the long run.

2) Remember that the more content you add, the slower your game will run. 

3) Adding a lot of CC will also slow down your game. 

4) Play with your Mac elevated and to be on the safe side on a cooling mat. Never play any games or work on your Mac on a pillow or comforter.

I think that's most everything. @Bluebellflora, did I forget anything?