Where is this relationship headed?

This is adorable and I believe you are headed in the right direction. Become and stay the best of friends, and maybe choose to take it further to a dating relationship when you feel both you and she are ready. It sounds like you two are staying indoors and not going public with your hand holding which could mean something, like she isn't ready for everyone to know she likes you, which could be a not so good sign. I am happy for you two and your friendship, I believe it will be a success! If you someday choose to be physical with each other before you get married (if you ever do), don't let it become the main part of your time together, just a little added fun :)