Term for a newcomer, who has already had some knowledge?

Solution 1:

I've always been a fan of the word 'tyro':

a ​person who is new to an ​activity: I ​look ​forward to ​seeing this ​young tyro's next ​ballet. (-- Cambridge Dictionaries Online)

It's probably only my imagination, but to me there's something enthusiastic about the word. That makes it fit a case where someone's taken the trouble to do prior research.

Solution 2:

Perhaps false beginner

someone who starts to study a domain (mainly a foreign language) from the starting level, although they already have a slight knowledge of it.

The noun initiate may fit, but it needs some context to avoid confusion.