I'd say something like:
This is perfectly natural. I used 日本語は instead of 日本語を to imply that you speak other language(s) and "聞くほうが話すのより得意" doesn't apply to these languages.
If you omit (は), it sounds more like you are actually good at 聞く, but if you keep (は), it means both 聞く and 話す are okay-ish level and 聞く is better than 話す only slightly.
In case you want to make the sentence more casual, you can drop 私は, and change です to だね/かな/etc.:
To make it even more casual, you can replace 得意 with マシ:
マシ is kind of a colloquial expression, and not many people use it for writing.