Hey, weve all got to start somewhere pal.
If this is the only mistake he ever makes working terriers, I think he will be doing good!
I have seen grown men who have been at it far longer make a bigger bals up of things, just to put it into perspective.
At least he has been open and honest looking for advice.
Some take longer to mature than others, and some never turn into what you want them to.
Wait till the season and try her again.
No shame in admitting you made a mistake.
Wish you all the best with your pup, and try and take as much constructive criticism/advice on board as y