I personally would never make a quilt for another coworker, ever again. The first (and only) time I did that, it didn't turn out well. We had a verbal agreement for amount of money to be paid, with the understanding that it would be several months before it was completed. At the end of about 3-4 weeks, the coworker started asking when it would be finished. And, even though the coworker had chosen the fabrics (from my stash) and the pattern, she kept telling me that it wouldn't look good. When the quilt was done, quilted, and bound, the coworker did not want to pay the original asking price, and told everyone else in the department that I was "taking her to the cleaners" for asking $250 for a hand sewn, hand-quilted quilt. In addition, she wanted me to give the quilt to her, and she would pay me when she had the cash. Needless to say, she never got the quilt, and that was that. I have never even considered doing that again. Anyone who gets one of my quilts has received it because I gave it away. to someone who apprecitates the time and love that goes into it.
As for you charging, that is up to you, but you will likely not make ay kind of 'profit' from it. IMHO, I think I would be more inclined to assist HER to make the quilt. To me, that would be more meaningful.