This is actually an HD skin (which are 128x128 px and 128x64 px), which is a feature exclusive to Bedrock Edition. Java Edition only allows 64x32 and 64x64 skins (You can quickly identify the resolution by seeing if the face is 8x8 or 16x16 px). PMCSkin3D has a tool to convert HD skins to standard resolution (Edit > Decrease Resolution 2x) but it rarely looks good. With a little bit of effort, you can probably salvage the dress and hair, but the face and headdress will likely need to remade from scratch.
Due to the issue you're describing, I assume you're on Java Edition. If so, you'll just have to either remake it or try to downscale it. If you're on Bedrock, then I have no clue what the issue could be.
P.S. The skin looks great, but I noticed you left some areas partially or fully uncolored (namely, the bottom of the head, the top and bottom of the torso, and the top of the legs), leaving them solid blue, which can look really ugly once you start moving around in game.
