Right here!
We will help the OP.
http://en.wikipedia.org/wiki/Tiny_C_CompilerThat is a start. You can see how somebody else did a very small C interpreter.
cats of course, he does not have to duplicate that effort. That would be pointless. But it should increase him to see how that that individual along with others developed a very small implementation of a language that is considered to be rather difficult.
In the original poster could call his new language almost anything he wants. There are no fast and hard rules about how you do something for your own entertainment. As long as it does not infringe on the rights of others.
Also, the language does not even have to be complete. It does not have to pass any academic standard. It does not have to be flawless. If it produces some result that pleases the creator, that is good. Whether or not other people would approve should not be the criteria. Now some point, he might want to publish his work. That would be another issue.
A simple interpreter with a built-in line editor can be made in about all I would say, maybe just under 3000 lines of code. I just don't remember. That was a long time ago when I did that.