I originally made false assumptions... since I believe such mistakes may be easily made, I'm going to update my original response with strikethroughs and add comments in bold to show where I\others may go wrong...
As I see it in the current comprehensive rulebook...
601.2 is the casting process. The keys:
601.2c The player announces his or her choice of an appropriate player, object, or zone for each target the spell requires.
601.2h The player pays the total cost in any order.
So indeed, if you couldn't wait until after targets were selected, you'd have to counter the spell BEFORE mana was paid!?! Not how I've ever seen it done. Technically true, but there's a key word that explains why this doesn't work as I expected when writing this...
But the clarity continues further:
701.4a To cast a spell is to take it from the zone it’s in (usually the hand), put it on the stack, and pay its costs, so that it will
eventually resolve and have its effect. A player may cast a spell if
he or she has priority. See rule 601, “Casting Spells.”
As diego's answers seems to allude to, no one has priority to act after the spell is initially cast into the stack... indeed the opponent could add other instants first if they wanted to. But you have the right to cast your counterspell onto the stack as you wish before it does resolve. **Rule 601.2i shows the caster has priority first after the initial cast. If they do not add anything to the stack, then the other player has the option to do so (see passing priority in 116.3d). I don't imagine this affects things a lot, but not knowing what cards there are now, could be entirely wrong! Still not sure what priority would have to do with this scenario, but I was wrong in my explanation.*
Perhaps confusingly, casting is just the initial act, and the stack goes on from there, allowing additional spells, including counterspells:
701.5a To counter a spell or ability means to cancel it, removing it from the stack. It doesn’t resolve and none of its effects occur. A
countered spell is put into its owner’s graveyard.
Note that if it removes it from the stack, it must already be in the stack, which means it must already be "cast", which means all of 601.2 took place first, including selecting targets. It thus appears based upon how WOC has defined cast (as just the initial declaration process) that it is impossible to prevent casting, which, at least for an old player like me, that seems would cause unexpected effects, as many cards might activate even if the spell is countered (or perhaps they've cleaned up the rules\writings since the era I played in... which indeed even included a separate category called interrupts for counterspells. So perhaps my concerns on card language have been taken care of.). Again, appears all this is true... but there's an additional term which I faltered at in my understanding throughout...
But further evidence of the process:
701.5b The player who cast a countered spell or activated a countered ability doesn’t get a “refund” of any costs that were paid.
Since targeting takes place BEFORE paying cost, indeed you counter later. Again true. But need to properly understand those terms
I see nothing odd in the wording of Jarad's Orders, the cards appear to be the target.
If that's so, then it's clear. Just as DavidZ and Hackworth suggested in the linked similar question given (At what point does a spell 'target' its target?). Targeting is one of the initial actions of just commencing casting (before mana is even paid), and so countering not only can be done later... but MUST properly wait until after targeting. And you were entirely correct in doing what you did.
Resolution:
What I'd failed to understand was the term target. I had assumed that whatever a card was directed towards was the target.
But that is entirely NOT true.
114.9a Just because an object or player is being affected by a spell or ability doesn’t make that object or player a target of that spell
or ability. Unless that object or player is identified by the word
“target” in the text of that spell or ability, or the rule for that
keyword ability, it’s not a target.
And
114.9. Spells and abilities can affect objects and players they don’t target. In general, those objects and players aren’t chosen until the
spell or ability resolves. See rule 608, “Resolving Spells and
Abilities.”
So MTG has a specific meaning of the word target, and only cards explicitly using the word TARGET must choose the intentions of the spell before the counterspell opportunity.
Because Jarad's Orders doesn't say target, you cannot wait until after he chooses (after resolution) to counter. Your play was not allowed.
Word meaning has gotten so complex these days!
