No, quite means 'completely' in the context of "I'm quite sure"
The definition of 'quite' is: completely, wholly, or entirely: quite the reverse; not quite finished.
jog
shh!!
In this sense, quite is an adverb, as it describes an adjective (the word crowded). Adverbs can describe both verbs and adjectives.
I believe it would be an adjective.
A bit longer than "shortly"