Hello.

I had read this manga a while ago, but can no longer remember its name. These are all details I can recall:
---Rather short, around 20 chapters, if not less
---Romance between 2 teenagers: commoner/poor girl - rich boy. Probably the genre is also "school life"
---Girl had one -or two?- younger siblings
---Ending is like this: guy initially seems to reject girl because the typical "we belong to different worlds" and goes; girl after a while decides not to give up and goes after guy, who is seemingly attending an event in a ship; some speeches, both finally accept each other in front of everyone, happy ending.

Could someone help please? Thanks.