Analyzing: How is Cadence an Alicorn if she was a Pegasus?

Hello every pony! Today I'm going to be analyzing how Cadence became an Alicorn if she was a Pegasus before that. Now I have plenty of ideas. Now this is a disclaimer, because I do not know if this is true or not. Now Cadence, had discovered a spell, even though she was not a unicorn. That spell was the love spell. Also Cadence had discovered the Crystal Mountains (Part of the Crystal Empire) Celestia allowed Cadence to be in charge of the mountains. Celestia found out that she was really responsible, and knew she would always be loyal to her. So she made a quest for her. Cadence was sent to defeat King Sombra. Cadence knew it would be dangerous, but she knew she had to do it. Cadence found a piece of the crystal heart stuck in a chunk of dark crystals. She knew it would only be a temporary time when King Sombra would be defeated. until then the Crystal Empire had to be a secret only royalty could know about. Cadence put the piece where the Crystal Heart belonged. It was powerful enough to free the crystal ponies, and banish King Sombra out of the Crystal Empire. Celestia was impressed. She gave Cadence a horn, and Cadence became a princess. That is what I think. If you dislike my idea, I don't care. It's what I think. Peace!