I concur with the two posters above.
I recently joined an IB in a consulting role, i had exactly the same fears you have when I was told to model which was something I had never done or seen done before.
Mate, it was easy. Chill out. You got through and with a bit of guidance from a supportive colleague you will sail through any model. Find a colleague nice enough and eager to help out, once you understand the basics it is easy.