For placement purposes, take the test. Although most of the other posters have already mentioned that it’s mainly native Chinese speakers that take the test.
For what it’s worth, my kid (ethnic Chinese but can barely speak Mandarin) got a 740 on the test based on his skills or lack thereof from weekend Chinese school. Self studied for AP Chinese and got a 5 and claimed that the test was a complete joke.
I also subscribe to the theory that AOs are not impressed by an AP/SAT FL score from a native speaker/ethnic member. Son took 4 years of high school French instead while his ethnic Chinese friends took AP Chinese.