I would go with the straight talking, be honest approach. Don’t lie yourself into a situation today, you may regret tomorrow.
Inexperienced drivers may find it harder to get a start, but every driver on the road started out like that. You have years of roadcraft behind you, although that may not have been in a truck. You are not a huge risk.
Get yourself a half day in a driving school vehicle to get relaxed about auto boxes and the size of the vehicle again. He honest about lack of recent experience during any assessment and a good assessor will take that into account. Tell them you’re a driving God and silly mistakes will make them suspicious.
And your age isn’t out of the norm today in this game.
You’ll be fine. [emoji5]