Thats great Matty and all you did wrong was install the bikes forks back to front
The retaining bolt should be on the front facing side. This increases the bikes fork rake and makes the steering less twitchy and less likely to crash. That and his feet wont hit the front wheel when pedalling and turning
Just turn the forks around so face the other way.
Nice try but take it apart and do it again
Unless you have a one off kids bmx that has backwards forks