When was Bilbo first considered to be an unusual hobbit?

Question

When exactly was Bilbo first considered to be unusual, as compared to other hobbits?

In The Hobbit, it is said that:

The Bagginses had lived in the neighbourhood of The Hill for time out of mind, and people considered them very respectable, not only because most of them were rich, but also because they never had any adventures or did anything unexpected: [...]. This is a story of how a Baggins had an adventure, and found himself doing and saying things altogether unexpected. He may have lost the neighbours' respect, but he gained- well, you will see whether he gained anything in the end.
_{^{The Hobbit - An Unexpected Party}}

This seems to imply that Bilbo was considered queer after he came back from his adventure (Quest of Erebor), as his dealings with Wizards and Dwarves became known in the Shire.

However, in Unfinished Tales, it is stated:

"Somehow I had been attracted by Bilbo long before, as a child, and a young hobbit: he had not quite come to age when I had last seen him. He had stayed in my mind ever since, with his eagerness and bright eyes, and his love of tales, and his questions about the wide world outside the Shire."
^{_{Unfinished Tales - The Quest of Erebor (Gandalf)}}

This, in contrast, seems to say that Bilbo was already quite different from normal Hobbits even before his participation in the Quest of Erebor, as he is shown to be quite inquisitive about the outside world.

Is this just an inconsistent narrative of the text or am I just misreading it? When exactly was Bilbo first regarded as queer (or unusual) by his fellow neighbors in Hobbiton?

_{Note: a queer hobbit is defined as a hobbit who does things out of the ordinary (for hobbits): having dealings with the 'outside world', meetings with other races etc.}

Answer 1

Bilbo had only been considered unusual _¹ after his adventure

¹The word "unusual" (or different) will hereinafter be replaced with the original "Queer" used by Tolkien.

It is true that for ever after he remained an elf-friend, and had the honour of dwarves, wizards, and all such folk as ever passed that way; but he was no longer quite respectable. He was in fact held by all the hobbits of the neighbourhood to be ‘queer’—except by his nephews and nieces on the Took side, but even they were not encouraged in their friendship by their elders.
_{The Hobbit: Chapter 19, The Last Stage}

After returning from his adventure his neighbours had begun to consider him queer and he had lost respect in the community. Although a few nephews and nieces seem to enjoy it, even if it was discouraged.

However, we must note that Bilbo had always had queer aspects about him. Having picked up some of the Took family traits, a family known for its adventures (and also having one member tall enough to be able to ride a horse, and inventing golf!). His "queerness", however, had not been noticed by others besides Gandalf (as mentioned in the Unfinished Tales) as he never had a chance to express himself.

It was often said (in other families) that long ago one of the Took ancestors must have taken a fairy wife. That was, of course, absurd, but certainly there was still something not entirely hobbitlike about them, and once in a while members of the Took-clan would go and have adventures. They discreetly disappeared, and the family hushed it up...

... Not that Belladonna Took ever had any adventures after she became Mrs. Bungo Baggins. Bungo, that was Bilbo’s father, built the most luxurious hobbit-hole for her (and partly with her money) that was to be found either under The Hill or over The Hill or across The Water, and there they remained to the end of their days. Still it is probable that Bilbo, her only son, although he looked and behaved exactly like a second edition of his solid and comfortable father, got something a bit queer in his make-up from the Took side, something that only waited for a chance to come out. The chance never arrived, until Bilbo Baggins was grown up, being about fifty years old or so.
_{The Hobbit: Chapter 1, An Unexpected Party}

As mentioned by @User001 Belladonna Took was indeed an adventurous person in her youth. Having been part of the "three remarkable daughters" of the Old Took

“ As I was saying, the mother of this hobbit—of Bilbo Baggins, that is—was the famous Belladonna Took, one of the three remarkable daughters of the Old Took
_{The Hobbit: Chapter 1, An Unexpected Party}

It is evident the the famous Belladonna had caused Bilbo (and possibly Frodo) to adopt part of her adventurous spirit.

Answer 2

Is this just an inconsistent narrative or am I just misreading it?

I think you’re misreading it.

When exactly was Bilbo first regarded as queer (or unusual) by his fellow neighbors in Hobbiton?

After he came back from his journeys. Before that, he was a perfectly respectable Hobbit. He was unusual in some ways — he was a bachelor, for a start, which the prologue to The Lord of the Rings tells us was unusual, and he was somewhat more learned than most — but he was nonetheless respectable. Certainly no one seemed to see him as particularly remarkable — or, at least, no one except Gandalf, who was shrewd and saw signs others didn’t.

There is no inconsistency. Gandalf saw even the child Bilbo as interesting; his neighbours saw nothing particularly worthy of remark about him until his return from Erebor.