Yes, the sentences are fine, but the third version requires a context of others who act differently, someone from whom you want to distinguish yourself - it puts the emphasis on the subject, which would be fine in the following situation:
Ich und 10 andere Schüler aus meiner Klasse sind krank. Die anderen haben beschlossen, daheim zu bleiben. Ich aber gehe heute (trotzdem) zur Schule.
Here you use the extra emphasis you get from the word order to highlight the difference between you and everyone else (whether that is dedication, stupidity or the irresponsibility of exposing others to the danger of infection depends on context).