I guess it would depend on how much you value her friendship and how much not doing it would damage that relationship.
Personally, I find it hard to do something that doesn't "speak" to me, as in like the pattern, material, want a gift for someone I really like or love.
Bottom line....would you agree to do it if she hadn't purchased the kit? If not, then the fact that she bought the kit is her issue, you didn't tell her to buy it. So if you don't do it you are not to blame.
I am proud of you that you told her you couldn't get to it until spring. Now I feel it might be a ggod idea to go one step further and tell her how much you would charge for doing it...and quote high!
I hate it when folks do things like this. So sorry, hope you figure out what you need to do.