Sweetie, if I can be of any assistance, call on me. You know I love discussing writing with you. You can do this. You will do this. Right now, all you are feeling is pressure, which can block your Muse. You have already written a lovely fic based on your second choice, so the first one is pure lagniappe. Think of it as dessert; you've already prepared the first course, dessert is a bit more fiddly, but ultimately will come together well, and people will enjoy it because it's more than they expected.