Marianne was so blown away by the announcement that she had won an award that she felt numb on her way to accept it. when she got to the microphone, she began to ramble and then everyone she could think of for voting and supporting her. the speech ran several minutes long and had no organization. was this appropriate for an acceptance speech

The answer is No.  

An acceptance speech is generally short, above all else. Even if the speech isn’t well-organized, the acceptance speech shouldn’t be too long that it impacts the whole event.

If Marianne received information that she was nominated, she should have considered making a speech nonetheless just in case she won. This would help her when she felt overwhelmed by her achievement.