Age 15 by Asagi Ryuu — Ongoing

Age_15_vol1_ch_01_000a_front

An Innocent third year middle schooler knows adult kisses.

Third year middle school student Anna has begun living with fourth year college student Ema, and is swung about by the tactless Ema.
Drawn in by the romantic designs of Ema, the once perfectly ordinary Anna, is brought into the adult world.
And then, she is shown the scene of a kiss between two girls... (From the back cover.)

Chapter 1 released Jun 1 '15
Chapter 2 released Jul 18 '15
Chapter 3 released Aug 22 '15 Het
Chapter 4 released Dec 31 '15 Het
Chapter 5 released Apr 25 '16