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Not yet...
It's not time for more advance 'play' and you have to remember Kasie's personality as well as her history.
First, Kasie can easily fit into your average young woman mind set. Your average young lady isn't that experienced, and sex is still relatively new to them--so you are missing a comfort aspect with more intimate activities. Kasie is more likely going to have penetrative sex several times before she becomes 'comfortable' with BJs. Once Kasie is comfortable with sex in general, she will want to give pleasure just as much as get pleasure.
Second, so far, we know that Kasie has had only one real boyfriend that led to sex. And the experience of that wasn't that good for Kasie as it would seem the boyfriend forced himself on her. So you already have a roadblock or at least that obstacle to overcome. Given time and Kasie gaining trust, yes, she will want and seek out sex as she becomes more comfortable.
Last, there is Kasie's personality. We only get little glimpses into Kasie's past, but what we do get is seeing Kasie getting dominated. Her mother, though not an iron handed tyrant, definitely ruled the household and Kasie meekly obeyed. That domination has made her more reserve and is on the shy side.
When Kasie does finally get 'laid' more than likely Derek will start something that Kasie likes. Then it will start to get out of control. Kasie's personality ought at the last moment realizes what is about to happen, hesitate for a moment and finally give into her own desires from the pleasure. Now with that kind of personality.... oh boy! Fear and guilt sandwiches!
Sure, the guilt of a taboo relationship and sexual encounter would be among the range of emotions, but fear? But the fear on so many levels. Fear of being in a relationship that isn't right and being emotional hurt. Fear of the rest of the world finding out. Fear she had unprotected sex. Fear that continuing having sex will result in pregnancy (at least to Kasie's mind).
Then there are the positives, small that they are. Most people get this little inner guilty pleasure if they have done something fun and naughty, especially when you know you gotten away with it. There too is the excitement that also goes along with the naughty, pleasurable experiences as well. At least those perverse positives do sooth some of the sting from the fear and guilt. Sadly being human, if its within reach its likely going to happen again (the sex in this case) no matter what you tell yourself.