Both of my boys loved puzzles and were really good at them in young age but they didn't really care about the edges either. It took a while before they started building puzzles from edges up.
If you have a small enough puzzle (50 pieces and less) edges don't matter that much. Perhaps that was their reasoning, perhaps they saw pieces which belonged together and that's all that mattered or they were simply not ready for such concept.
Let your daughter built whatever way she wants to. You may try to build most of the puzzle for her and ask her to put in the last few pieces. May be that will interest her if not put it aside for a few months and try again later on.
