Why have my strings started buzzing all of a sudden?

So I got a new guitar, and for the first two weeks I’ve been playing it almost daily and it didn’t have any problems, but as of a couple days ago, between I want to say the 11th fret and 14th of the high E, and there’s some buzzing on the 12th fret of the B string. Like no note is played, so I don’t know if action is high, or if maybe the guitar was sitting a while before getting shipped to me, and it needs new strings already, but I don’t know what is happening, since as stated it was perfectly fine until a couple nights ago.