That's good in a way!
Look, I know some people who don't give a crap about other people, and are always down and unhappy and are not friendly at all. These guys are so boring and depressing!! It just makes me want to get the hell out.
At least someone nervous is always exciting, speaks with enthusiasm which a lotta guys don't have, and are never boring. (At least for me HEHE!)
When you're nervous, you have too much energy and you stumble on yourself because you want to make a good impression. If you weren't so busy in thinking how to make a good impression, you would be left with only the energy!
Now that you know that, you gotta do is to convert that energy in something useful. And then you stop being nervous, and you start to get excited, enthusiastic, which is good, if you don't let it get out of hand. So speak slowly now!! Your voice will still have a good tone of enthusiasm, and to avoid being annoying, don't speak so much. John wayne said: Talk low, talk slow, and don't talk too much.
So the best advice is : Control all of that energy and you're cool!
And remember that other people's opinion of you isn't terribly important. Why should it be? What happens in they don't like you? The answer is nothing. Nothing at all.
And post back in a week or two if you make progess!