Want to be an Animagi
Dear Professor McGonagall,
I have looked through many books and have not found out how to become an Animagus. As you know, I’m a hard working student and I am willing to make the change… please get back as soon as possible.
You might notice a distinct lack of Animagi among the students at Hogwarts. Indeed, I dare say there are none, currently. In my decades of teaching, in fact, there have been only three that I know of, and they came by their ability illicitly, and never registered with the Ministry, as is required.
Animagus transformations are very advanced forms of Transfiguration. As such, the skill is taught only to those who go on to study Transfiguration for their post-NEWT studies, and not all of those who attempt the transformation accomplish it. Should you wish to pursue the possibility, I suggest you apply yourself to achieving an Outstanding on both your Transfiguration OWLs and NEWTs.
I look forward to your excellent performance in class.