MrJerseyGuy-
Communication is key to a good relationship and there are many ways to communicate (though, verbally and in writing are usually best) whether someone has a limit or someone doesn't. Unfortunately, not everyone knows what they want nor does everyone communicate what they want. But, usually, a person will communicate what they don't want and it seems she is doing that so it sounds like (though, only she can really tell you, for sure) you are doing fine. One thing I would suggest, introduce her to the list and share with eachother the results of the list http://www.bdsm-education.com/checklist.html sometime to get a better idea of what her limits are (might help her, too) and what direction she feels comfortable with and which she doesn't. Also, another suggestion, maybe ask her to start a journal especially for you so that she can express fully what she likes and dislikes about your time together so that you know what directions to go in and what sort of things to concentrate on. And, of course, safewords are very good for quiet non-communicative subs. But, I tend to feel like the safeword thing is the cherry topping rather than the filling of the cake. Communication either verbally or in writing should be the filling, in my opinion.