There is no official or exact age for Tsubaki, however, she is often described as a young teenager. This is supported by one fact where Tsubaki herself stated that she is at “that” age where she constantly thinks about boys. Our research led us to conclude that Tsubaki is around the age of 15 by deriving information from fan discussions on Reddit, especially from a Redditor named randyripoff, when he/she commented in one Reddit discussion about the 12th episode of the show.
According to Kunoichi Tsubaki no Mune no Uchi Fandom, Tsubaki’s height is 5 ft and 1 inches. The fandom also mentions her birthday, April 1.