It looks fantastic for your first costume I bet your going to be great at making costume's. Things I would fix are maybe the ribbon change to bias tape if possible matte materials show up better in picture's and then I think your bow could use some work. For mine I do a measurement over the nipple of nipple to nipple xD I know sounds odd lol but it really helps once you get that measurement you times it by 3 and follow this tutorial. It just insures that the bow won't be to large on your body since that tutorial has one specific measurement and there bows are that length. I'd also probably use a lighter weight interfacing for the bow it looks a bit to hard or you may possible only have it on one side. I actually only interface the top area of my bows and leave the bottoms dangle but that's just a personal preference thing.
I probably would have pleated the skirt myself but lots of people do the ruffled skirt effect as well you could look up tutorials on how to do box or knife pleats if you wanted to re-do the skirt but I wouldn't really sweat it it looks pretty good honestly.
you should get a picture of it on as costume's always look different on and then of your gloves boots and arm rolls as well.