I haven't been quilting long and had never sewed before. That feeling of fear, mixed with exhilaration, is
very fresh in my mind! I survived to go on and make more quilts and smaller projects, most of them better than the last.
As well as all the things I've learned along the way (and that learning curve has been steep, I can tell you), the most important thing I've learned is to
relax and
enjoy the process! You may make mistakes, but so what? It's how everyone learns. Anyway, it's not a 'mistake', it's a 'design opportunity'
If you get stuck, there's the internet, this board and probably your LQS where you did your class to help.
Good luck and be sure to post pictures when you're done.