- Modern high level C++ has very little to do with C (you usually try to avoid pure pointers wherever possible, you don't do explicit memory management, you don't use C style I/O, preprocessor constants etc)
- You're most likely not risking adopting a bastardized C/C++ mixture, it is almost impossible to avoid it, because as a beginner, you do not have the experience to discriminate between what you need for C++ and what you don't.
- In C, simple programs are much harder to get right than they are in C++, because beyond "Hello World", you need to work with pointers or pointers in disguise (arrays), manual memory management, the syntax is much more restrictive in a lot of ways and so on...
Don't get me wrong though, I am a huge C geek myself, but it took me years to let go of old C practices when I switched to C++ and even today as a professional software engineer, I sometimes have to force my self to do things in a clean way instead of the quick C hack way.
Oh, and if you can, try to find a book that covers C++11. I don't know whether there are any beginner books on this topic available yet, but with C++11, it becomes much more accessible to beginners.
But in the end, I typically advise people not to begin programming with C++ before they know some important concepts. It is possible, but it is also quite frustrating from time to time. You better start out with an easier language like python (or even this horrible C# thingy )