I too have done quilts for "friends". At first it was fun. But there a lot of stress that goes along with it. Just do you best. Reinforce that you are new at this. As you grow in your skills you can charge more. I would suggest that set a price in the future ( you will understand after you do one). Also, remember this is your hobby. Stress will interfere with the fun of it. I charge for the fabric right after I buy it, and I only by quality fabric, as this affects the whole project. I charge .5 cents per square inch. You can also charge per square foot as some one else recommended. Also, I never work under that close of a deadline. You never know what could come up. Reduce stress and enjoy what you are doing. :D