Help

MammaRaptor

I am new with DSLR cameras. I have always just used a plain point and shoot Nikon! I am debating on which lens I should purchase. I want a lens that has many options for shooting everything! I have been really eyeballing the 18-105mm f/3.5-5.6G ED VR AD-S DX Nikkor, but I am feeling really uncomfortable with the mount being plastic and not metal. Also, I would not be happy to spend the money to have something happen because of the cheaper material used for a more affordable cost. I have a the D5100 and I have been debating on getting a lens going up to 200mm. I am going to be helping a friend shoot a wedding (for experience and to help out only) and I really want the 18-105mm for the wide range of lengths I can shoot with. Any suggestions on a lens that would be ideal?? Some help would be great appreciated! Thank you.