Mistakes happen-- especially with your first experience in something.
You have to understand that it was just a mistake and learn from it-- and become a better person, rather than panic and feel like a terrible person.
You need to gain experience in order to get better at things, right?
Everything takes practice.
And if she still likes you; I would suggest taking a bit of a break and explaining to her that it's your first time- that you need to both be open and communicative; and perhaps try again?
For right now, though...
Perhaps try doing something you like to get your mind off of things.
It's not the end of the world- just a lesson in life that you can learn from to help you grow.