Yomeiri no Susume: Taishou Onzoushi no Gouin na Kyuukon

It's the Taishou era, and Ranko Hanamiya, a former young miss, is 24 years old and works as a waitress at a high-class café called Cassiopeia. Her family complains that she's too old for the job and that it's embarrassing, but she doesn't care.

One day, while at work, she suddenly receives a gift from a handsome stranger, a young university student. Her co-workers are all in a frenzy, but Ranko, who has no idea what's going on, keeps her cool. At home, however, a terrible problem is brewing. Viscount Chounabashi's family wants to marry Ranko. In fact, their grandfathers have promised to marry their grandchildren to each other. However, Ranko, who enjoys her work and is not interested in marriage yet, refuses, but her parents, who want to keep up appearances, push her to go to the Chounabashi family. And what's waiting for her there on the day of the wedding is the unsociable young man who gave her a present at the café, Ichirou!?

(Source: Shogakukan, translated)