Unable to do Pullups

[aurelius]

I have decided to change my routine to include pull-ups, but last night when I tried to do a set I couldn't do more than two with proper form.
My question to everyone is should I continue with the pull-ups and hopefully in time get better. Or am I wasting my time and energy and should do something like wide-grip pull downs which I am good at?
Your help is appreciated.

What is "proper form" to you?