First, I think “vintage” is often used as such a broad term. For me, it’s a name that was popular about 90-120 years ago. And, yes, I’d agree with you that it has to feel pretty tied to that era, meaning it was actually popular or was worn by a famous person, character, etc.
I also like how [name_f]Elea[/name_f] describes it in her list on British [name_u]Baby[/name_u] Names:
Vintage Names - British Baby Names
(A few on this list are more British-vintage and don’t feel particularly vintage to Americans – e.g., [name_f]Hermione[/name_f], [name_f]April[/name_f], [name_f]Vanessa[/name_f] – those last two in particular are definitely more 1980s than vintage in the US. But, overall, I think she makes a good list!)