The poem opens with questions every young person gets asked: who will you be, where will you live, whom will you marry, what language will you speak? The speaker doesn't answer them in a neat, grown-up way. Instead, the key word is "if." Saying "If I grow up" makes the future feel uncertain, even a little fragile, as though adulthood is something that can't be taken for granted.
What the speaker does want is freedom. She pictures herself gone "with the wind," where no one can catch her. She also hopes to write stories that last, carried "through years and depths," and that mean as much as a good book does. In the last stanza she shrugs off the details of marriage, place and language and cares only about the shared life.
The mood is wistful but hopeful, with a casual, honest tone ("Dunno where and when"). Underneath the lightness there's a quiet worry, and a strong wish to matter.