Kali, my 11 year old bitch, was taught to sit. Every time I took her in the ring she would sit down as soon as I stopped running her. She still does, bless her. Mind you, she is thick as 2 short planks

I have taught my other dogs to sit, but not every time I stopped, which is where I went wrong with Kali. If you teach the pup to 'stand' and 'sit' alternating so that the dog doesn't get complacent you should be ok.
As for being nervous and making a complete idiot of yourself, well I think we all feel like that almost every time we go in the ring. It's sometimes worse than sitting exams ;) BUT we all get through it and thoroughly enjoy it - especially if we win. :D Try it, you might just like it :)