Besides the fact that it wasn't established how the Holodeck works early in the season, if I recall correctly the first scene of it in Encounter at Farpoint established that the Holodeck cannot create living matter at all - only landscapes. It wasn't until after a Holodeck "upgrade" prior to The Big Goodbye that the Holodeck could create people and other characters.
If we accept the TNG S1 episodes in their production/airdate order, rather than playing with the odd stardates, then the first time holographic people are seen is "Code of Honor", with the sparring partner. The second time is "The Big Goodbye" where there is indeed mention of an upgrade, and apparently Picard has never before had to face the fact that holocharacters would react to his Starfleet uniform.
Yet in "11001001", just three episodes later, Riker creates a jazz joint full of people, and is already familiar enough with the concept of holopeople that he can quickly tell how Minuet is something special and different again.
(If we go by stardate, "The Big Goodbye" gets bumped to the end of the season. Too bad that Tasha is alive there, or otherwise the stardate order would work more or less fine.)
We can't really tell whether our characters are impressed by the very existence of holodecks and holopeople when we first see them interact with those. They could simply be impressed by the improved quality of those things aboard the E-D, as opposed to their previous assignments. Picard for one spent decades in an obsolete rust bucket on the outer fringes of the Federation - he might never have had a high performance holodeck available to him before "The Big Goodbye". Riker transferred from a less advanced starship as well, before getting all gushed up about the hologarden in "Farpoint". But then again, we know that the younger man is a connoisseur of holotainment, as evidenced by his soft-porn tabletop display. He'd probably have sought the best the Federation can offer, and still the E-D 'deck impressed him.
Nevertheless, there's nothing to say that holodecks (although perhaps by other names) couldn't have existed back in the 2260s, as featured in TAS "The Practical Joker". They just had a slightly more cartoony look back then.
Timo Saloniemi