You are very welcome ^_^ inspiring someone else to write is a very high compliment.
As for where to start… I would start with reconnecting to what ever drove you to write this story in the first place (this might sound weird, bear with me a moment). It could have been just for fun (nothing wrong with that), or maybe it was for something a little more specific your heart wanted to do. Connecting with your heart on what it wants to say or do helps create a sense of direction for both the story and your MC.
Lets throw out some ideas: In your story, her getting home seems like the big priority, that might seem plain or obvious, but there is a LOT you can do with that! Maybe she is taking care of a very sick family member, which gives the story a sense of urgency and drives home a feeling of familiar care. Or, by contrast, maybe she rushing to get back home to escape having to take up responsibilities in faerie-tale land (a fun ironic twist) or needing to establish a place/life of her own there. In the first example, when you take her through a day in her life, you can see her being resentful of having the extra burden of taking care of someone, even if she loves them; this gives her the central struggle and room for character growth. In the second example, maybe you see her out partying all the time with a group of less than healthy friends, or maybe she is simply not able or willing to see her own potential and lacks confidence; this means that her comfortable world shatters when she is no longer in her world, and through the trials she endures in faerie-tale land, grows in both capability and confidence.
The above are just two examples. The important bit is to figure out what it is your heart wants to say/figure out. This will help give your MC a life of her own, and make the story satisfying to write. If you are having trouble with that, a good trick I found was to think about what other story/movie/show resonates with me and watch/read them again with a critical eye. The big moments in those stories are flashy and fun and easy to remember, but it is so often the quiet moments that give them the depth and truth (even in simple fun adventures) that lands them in my heart. Cinderella escaping her home, for example, wouldn’t be so significant without her first suffering her sisters and mother. And the prince wouldn’t have fallen in love with her if she let the cruelty of her mother and sisters change who she was.
Again, I hope all that isn’t overwhelming, lol. And again, the most important bit is to have fun. I guess the point I am trying to make is that your heart knows what it wants to do and is smarter than we give it credit for; watching the good stories that other people have done simply helps our brains catch up.
Honestly, between slowly getting familiar with the forums, my own WIP, and real life, I’m a little overwhelmed. But feel free to post more if/when you write more 🙂