Here are the known character birthdays and their current age in the manga (as of April of Yuno’s third year).

May 5th – Yuno (17)
June 15th – Hiro (18)
June 27th, 1964 – Yuno’s mother
August 3rd – Ume Aoki
October 10th – Miyako (17)
November 3rd – Sae (18)

??? – Nori (16 and will turn 17 by next April)

??? – Nazuna (16 and will turn 17 by next April)

??? – Matsuri (15 and will turn 16 by next April)

There isn’t any birthday/height/blood type data on Nori and Nazuna yet, since the original tenants’ birthdays were revealed in an anime document from the first season. Ume has confirmed all of them. They should have started high school at 15 and may have turned 16 at any point during their first year. Chika happens to be the same age as them.

Strangely, in neither the manga nor anime, no one is ever seen celebrating a birthday. Despite this, the birthdays are canon in the anime. When S3EP09a takes place on November 22nd of Sae and Hiro’s first year, both Yoshinoya and Misato refer to Sae as 16. If Sae did not have a birthday before then, she would still be 15 as most first-years are. An oddity occurs with S4EP08B which takes place on November 3rd, in other words, Sae’s 18th birthday. This is not acknowledged within the episode.

Here’s a quick reference for everyone’s age relative to Yuno:

+3: Misato, Riri

+2: Arisawa, Toudou

+1: Sae, Hiro, Natsume, Nakatani

0: Yuno, Miyako, Mami, Nakayama, Kiyomi

-1: Nori, Nazuna, Chika

-2: Matsuri