Hey. I'm also on a mac.
So I can ensure you that it is possible.
Please check if you get sound on headphones when you plug them into the macbook.
If this works your speakers might not work right.
Check the system preferences > audio > output. What do you see there?
The next thing to check finder > programs > utility > audio midi setup.
Check the internal. What do you see there?
In Cubase check Devices > ASIO > what is set as the ASIO driver there?
Mac Mini (Mac OS X 10.8.5; Intel QuadCore i7 2,3GHz; 16GB RAM; 1600MHz Frontbus), Steinberg UR28M, Alesis M1 Active Mk2, AKG K271 Studio, Beyerdynamic DT 770 M, Focusrite ISA One, Shure SM7b, Yamaha KX 49, Steinberg CMC CH, PD, TP & QC, Steinberg Cubase 7.5.20, WaveLab 8.0.2, HALion 5 (Version 2.2.5), HALion Sonic 2 (Version 2.2.4), Halion Symphonic Orchestra, Dark Planet, Neo Soul Keys, The Grand 3 (Version 3.1.0), Padshop Pro, Groove Agent 4, Native Instruments Komplete 9, Steinberg-Yamaha Vintage Channel Strip & Vintage Open Deck & Vintage Stomp Pack
Life is too short for realtime-bouncing..