The limit is 650. I wrote a new personal statement (first one was too cheesy imo) and it only went to 350 words.
No one can really say without reading it. However, I personally think it’s fine to have a short personal statement. It’s better than having a bad one that meets full word count or filling up the essay with unnecessary fluff. Have an adult read it for you and get their feedback on it (ex. an English teacher).
350 is almost certainly too short.
While you don’t have to meet the 650 limit, 350 sounds like you haven’t fully fleshed out the idea.