I would recommand to build one with help from someone more experienced. Just don't ask him or her to build it for you, assist him or her in doing so. You will learn a lot and you will be able to fix it yourself in the future.
The only tricky parts in a fixed gear bicycle is the headset, everything else is straightforward. Well it's not that tricky but your life depends on it so I wouldn't tell a newcommer to install his or her first headset without assistance.
Fixiefiddled that for you.