I've been a long-time DOS/Windows user myself (DOS? What's that?

), and outside of using a MacIntosh and PowerPC while in school, didn't own anything Mac related until 3 years ago when I picked up a late 2011 15" MacBook Pro thru my previous work at the time. At that company, everyone was using MBP's or Airs, so I got hooked. I've maxed out the RAM (to 16 GB), and upgraded to an SSD, and it's still going strong today.
Yes, though viruses aren't as commonplace compared to Linux/Windows, I would still recommend getting one as a precaution. I'd also recommend getting a VPN too when you're at a public wifi location. If you still need to run something in a Linux or Windows environment, you could dual boot via Boot Camp. I don't use my MBP for gaming much...I let my console and Android devices handle that.
Congrats on the purchase, and enjoy!