 If you liked
Happy!
|
 ...then you might like
Act-age
|
They're both about a poor but talented girl, who alone raises her younger siblings and overcome challenges to succeed in their respect fields. Both manga heavily focus on the protagonist and her development throughout the story.
At the beginning Act-Age feels like a vanilla version of Happy!, there's not nearly as much suffering and struggle, however it soon takes his own identity. While Happy! is about overcoming external problems, most of the conflicts in Act-Age are internal, they're both interesting on their own right.