"My Japanese is not so great" in apologetic (んです) form?

Question:

I know a few different ways to say my Japanese isn't the best...however I'm not sure how to place it in んです, apologetic/explanational form. ( I don't even know if you CAN do it)

If it works, and doesn't sound akward in conversation, could I please get an explanation?

Answer:

If you want to say like "my Japanese isn't the best" using (んです) form;
私、日本語がそんなにうまくないんですが、
私、日本語がそこまでうまいわけじゃないんですが、I
私の日本語はたいしたことないんですが、

Hope this is what you asked...