I have postponed upgrading to Yosemite, primarily due to a number of reports that the upgrade causes significant WiFi / Internet connectivity problems. I assume that, since your MacBook Air is quite new, it doesn't have an Ethernet port, which means that you rely on WiFi for Internet access. Some users have posted fixes that worked for them, while others have resorted to downgrading to Mavericks, the previous version of OSX, to resolve the connectivity issues. If you are a self-described "non-techie," these actions might be something you'd rather avoid. Ultimately, of course, the decision to upgrade is yours to make.
While it's true that most people are apparently having no problems after upgrading to Yosemite, the potential for issues exists, and unfortunately, Apple has been silent on the problem. They did release an update that supposedly fixed it, but there are reports that it didn't work for some users.
You can read more about the connectivity issues here on MacRumors:
https://forums.macrumors.com/threads/1820083/
https://forums.macrumors.com/threads/1816842/
and at Apple's own Support Communities:
https://discussions.apple.com/thread/6601963
(Warning: this thread has nearly 250,000 views and 1,300 replies!)
Edit: If you decide to upgrade (or even if you don't), I strongly recommend that you backup all of your important data in the event you ever need to erase your drive and restore your operating system.