She was still being trained throughout that time, just with the last two years in active life risking situations.
It was the cage match thats bothering me. Perhaps it was only me, but I saw the defeat there as her being taken over by the trauma, with us actually seeing it. In this match we don't see any issues until the final strike. So I can't see the trauma being much of an excuse as they've been showing us when it takes control.
I see everything up to that point as being her skill alone. And thats what makes it disappointing. Yes Korra should have lost but not to that extent.