I am curious about how to remove the first commit in git.
What is the revision before committing any thing? Does this revision have a name or tag?
There is nothing before the first commit, as every commit is referring a parent commit. This makes the first commit special (an orphan commit), so there is no way to refer to a previous "state".
So if you want to fix the commit, you can simply git commit --amend: this will modify the commit without creating another one.
If you just want to start all over, delete the .git repository, and make another one with git init