Does ...我的中文知识不足够的，所以不可能帮你们... sound awkward?
Well, I can understand your meaning very well, it's good!

For some recommendations，

“太好了！”

There's an adversative after it, you can use "只是" (but).

“很不幸” should be “很遗憾” (unfortunately)

“我的中文知识不足以帮到你们”

Well, just for the second sentence, I can't imagine what do you want to mean by "我很兴奋的"... but you can use “支持你们！” (support you)


  太好了！只是很遗憾，我的中文知识不足以帮到你们。支持你们，加油！