you can say我的中文没有我所想的那么好

我 想要的 汉语 水平 还 没 到了。 = wǒ xiǎng-yào-de Hàn-yǔ shuǐ-píng hái méi dào-le

My Chinese is not as good as I want it to be. 我的中文没有我想要的那么好。 我的中文没有达到我想要的水平。 I agree with the first part of Ben's answer, but this sentence doesn't necessarily imply that my Chinese is not good, my Chinese is maybe excellent instead, but I still keep studying and want to improve it.

https://www.youtube.com/watch?v=2XTBwvi0h2E This got my friends and I through many a weary class day, when I first started learning. That being said, Ben is correct："我的中文不太好," or "我的中文差不多了“ would be more natural ways to say it. Good luck!

Chinese is not spoken in that way. So a direct translation - "我的中文不如我希望的那么好" - is very awkward, though it may be loved by advocates of 洋派现代汉语. A more natural and Chinese way of expressing these sentiments is "我中文不好，希望可以提升。" A good piece of advice to you is to learn Chinese without using English at all. Go to a Chinese teacher, use a Chinese textbook, and forget about English while you are learning or practising. That's the way that the Alliance Francaise teaches French anywhere in the world - completely in French from the first minute, never ever using another language. That's the most effective way of learning a language.