It depends on whether you treat the answer as "like a native" or "I am a native". The word native is etymologically rooted in "born into it".
To sum up: You can speak a second language better than a native and have a proficiency of a native speaker without being a native speaker of the language.
Running is beneficial for knees and ankles over medium to long timeframes. There's a 100 year old guy that runs 10k every day and his knees and ankles are doing fine.