I tried your mesh and it didn't crash my Workshop. I do see a couple of problems with the mesh though that you will need to fix before you or anyone else is to texture it.
1) The way that you edited that mesh -- by pulling a row of vertices down and out -- is going to cause problems when your Sims move because you still have part of the original mesh under the skirt that will be poking out. See Photo #1 that I attached below. You would be better off using a different mesh to make this dress with so you are not folding the dress on itself.
2) After you pulled those vertices down and out, you did not update the UV map for that mesh. When you make changes to the position of the vertices that will then in turn affect how the mesh is mapped, which in turn affects how you will texture the dress. Any textures you put on the area that you stretched will stretch as well, since you did change the necessary changes to the UV map. See Photo #2 to view how the pattern is stretching.
If you can wait a week or two, I can give this dress a try for you -- new mesh and all. I have promised myself to other people for some other projects right now, so I can't get on it for at least a week or so. I need to finish these other projects first.