So typing on an iPad screen might be ok if you are just keying a few notes. Will a few notes enable you to be successful in your studies and responsibilities? Probably not.
In fact now, many iPad users have purchased additional accessories for their iPad including a keyboard for increased typing speeds. If you are a hunt and peck style typist, choosing a keyboard won't likely help your typing skills; however, if you are a typist that can type 50+WPM, you will benefit from having a keyboard.
This following article might help you choose your next iPad keyboard. My personal two favorites are:
Logitech Solar Keyboard $100-$129