Building a wood gate too hard for DIY newbie?
In order to build a gate properly you need the Z/reverse Z frame and build everything around that. 

How to design your fence properly

The key points are the intersections where the 45° lumber meets the horizontal and vertical lumber. You need good solid joints there. The rest is just decorations. For gates that wide I'd still put wheels on just because it'll be difficult to secure such a heavy load to the wall without some serious lags in very good brick. 

Here's an example of one: