To change or update the title of your topic, just click the EDIT button for your post, and make the edit to the "Subject" line. Remember you are still limited to a max of 60 characters.
Up to now, no one has said you have to be in the 1st post for the topic.
So, if you have been telling the steps of repairing your rv after an accident or ...... and have several of your posts and responses, you have to make sure to go all the way up to that 1st or thread starter post.