I was previously using the MacBook Pro 17" 2009 and am already connected to a Dell external monitor running at 2560x1440 60hz. You will have no issue running an external display with that spec of yours which is more powerful than what I previously have.
From
http://graphics-cards.specout.com/l/6021/Intel-Iris-Graphics-6100,
it can supports up to 3 displays with the above max resolutions. So it means you will have no issue running your own internal display along with another external display. I will recommend that you connect to the external display with DisplayPort 1.2
If you are new to Mac OS, then it's good for you, so you now have the chance to use a unix system. It will be of good help to your understanding on unix systems if you know how to operate the Mac OS X effectively. Life is more than just one OS, get yourself exposed to new things. Learn Mac OS with an open heart and you will find it is very different from a Windows. When meet up with issues, just search on the web and overcome it. Learn to do things the way it is designed in Mac OS X