The Nikko G nib is a firm favourite for all modern calligraphers and perfect for beginners.
I teach with this at all my workshops, it's medium flex and a great all rounder.
 
The nib will have a rust repellant coating which needs removing before use. Please soak the nib in hot water and use a toothbrush to rub off the coating.
 
Our nib tin is a great way to keep your new nib safe!