Now this is a very interesting thread. First, you must keep in mind that progression always go fast then stops,get fast again, slow downs, slow downs, stops, and slowly comes up for ever...
I have struggled with building confidence over time. Now when I recently rode with competiton elites or experts level riders, they just said height was a stage. You don't have to be afraid of the height, you will struggle to get over certain height but when you want to get over something smaller, you don't even doubt about it. All you can do then is train.
Even when I learned I was sick, I wanted to waste no time and shred stuff. This didn't happened just because I was angry about my whole life, it's just because I had never done it.
Every move you do for the first time, always remember that you do it for the FIRST time everytime so you don't really know exactly what will happen except in street where all walls just differ by the height.
So train hard and push yourself physically to get better. I even had mental training when I took training seriously. It really helped me a lot! So eat well to have a lot of energy, get motivated on the bike by watching some great vid before going out riding. Basically, just ride happy!
And enjoy!