They wouldn't have given you the job..

When I talk to people about my new job and my worries about my skills, the following phrase keeps being repeated over and over:-

'They wouldn't have given you the job if they didn't think that you could do it!'

I know it's supposed to make me feel better but you see people are missing the point. The reason I am stressing is because of that statement. 'They' do think that I have lots of .NET skills and experience and can do the job, whilst I know that I don't have that experience. And that is what is worrying me!