I have a 14x29 and its solid as a rock, I'm 5'9" and 80 kilos.. Good looking too

I rode a 12'6x26 two weeks ago
And struggled on it. Sure it'd soon settle in with time on it but that was too much for me.
As suggested above, go wide, you really don't need narrow unless your aim is speed.
Wide = easy everything...
Enjoy..