Lilac Time

14-year-old Jill is an honor student with excellent grades at St. Mary's Academy, but also a problem child with bad behavior. She was love with her childhood friend Ace, but she's now crazy about her female teacher, Alicia. Alicia is beautiful, kind, enthusiastic, and also a free mind, and Jill's feelings for Alicia went beyond aspirational and are now closer to love. Meanwhile, Jill's best friends Marge and Kathryn all fall in love with Jill's older brother Graham...

(Source: Beaglee, translated)

Note: Includes the one-shot "Ame no Niou Mado (雨のにおう窓)".