Hi
We have 2 budgies that are a similar age to yours....and also had the same issues in training, however they now lets us put our hands in the cage and they will perch on fingers, arms, shoulders once out of the cage every time
It takes patience (sometimes very annoying i know) but the birds seemed to gain confidence and trust quickly once that initial barrier is broken
e.g. they stayed in the cage every time we cleaned it out and eventually learned to trust us (these days when we clean the cage they either sit outside the cage on top of it or even on my shoulder while i do it
most important things to do is talk to then when ur hand is in the cage, praise them when they do good and dont overdo it with training
Let me know how you go
Frank Steamer