The name changes were a bit confusing, but not too bad.
Can you really get in the British services that way? You used to be able to get in the US services like that, but I don't think you can any more.
They require a fair bit of education. Test, too. Written as well as physical.
Enjoyed it.
Author's response
Needless to say a bit of freedom was taken with the rules for entry. I did however try to keep it plausible. Harry did not become a pilot or any type of officer. He's just a worker.