I don't know how many people have had similar experiences to mine, but during grad school and shortly thereafter I have actually found myself having to be more flexible and willing to try out different areas of this field because of the limited number of positions available to people early in their careers (and unlicensed), so you may have more time than you expected to decide which position is best for you. I entered graduate school with specific plans of the setting in which I would like to work when I'm done, and things have not quite panned out as I had hoped. Between my practica and internship, I worked in community mental health, an intensive day program and a school. Since receiving my doctorate, I have worked at two completely different private practices, one that specializes in children on the autism spectrum and one that works primarily with low income adults (and I have been doing forensic evals part time the past two years as well). In my opinion, that's one of the great things about a clinical psychology background; people from my graduate program are now working in a whole variety of settings, and my experiences show that it is possible to try out the different settings. Of course, I don't think that's doable in the long term, so I am trying to focus my experiences more now, but honestly, these different experiences have helped me to more definitively decide exactly where I would like to work and with whom. And yes, sometimes you have to explain in an interview why your experience has been so varied, but so many other people have been in a similar situation that as long as you can explain your various jobs in a positive light, they seem to understand. Plus, at my current practice, they now refer most clients with lower cognitive functioning or school-related issues to me, so you can use previous experiences to become your specializations. So hopefully my experiences will give you hope that having all these interests doesn't necessarily hurt, and you can give them all a try without particularly negative consequences.
Oh, and as for your concerns about forensic psych in particular... my coworker told me yesterday that forensic programs graduate are still relatively new, so as long as you have a strong testing background many forensic sites will take you (he and I both work part time testing for the courts with clinical psych training, so our experiences both support that assertion.) So that setting may actually be one of the more flexible ones... for now, at least.
