I don't know; as someone who's been an adult for quite a while now, I have to say that I prefer being an adult. But only because I really learned along the way and genuinely take responsibility.

That said, let me say to you: don't be in too much of a hurry. There is value to every stage.

Why are you about to fail this assignment? Is it a paper that's due or something? Maybe you can still pull it out. Just do the best you can under the circumstances.

Or, consider talking to the teacher if you had a genuine problem one way or another.