there are 3 forms of interrogative sentences in French
- Ta jupe est-elle très différente ? this is the formal, academic and written form. The subject noun (jupe) starts the question and it is repeated with the matching pronoun (elle) in the Verb-Subject inversion.
- Est-ce que ta jupe est très différente ? this is the standard form, commonly used in speech and writing. Easy to use, it starts with "est-ce que" (pron. eskuh) then the sentence is built as in the affirmative form (subject + verb).
- Ta jupe est très différente ? this is informal, and used in speech: in writing you just add the question mark and in speech, you simply raise your voice on the last part.
There is a whole Skill (unit) titled "Questions" + Tips and Notes + thousands of comments on the forums. Since you are level 25, you could not miss them.