Good morning, Leo's,
Cancer woman here. Cancer's aren't really all that secretive. If it stays secret too long, she could start wondering if you are ashamed of the relationship and don't want anyone to know.
Also, you are correct about letting us stay in our shell until we come out on our own. It could take a while. If my feelings get hurt, I sometimes stay alone for 2 - 3 days.
Sounds like your cancer woman isn't sure if she even wants this relationship. We are ususally pretty sure of what we want and don't want.
Don't try to contact her everyday. 2 - 3 times a week would be plenty until you are strong in the relationship. We have our moods, but we are very strong lovers once the relationship is solid.
Hope this helps,