You need at least 25,000 points to get your own advice column. However, we already have a tween club for discussing things.
We have given advice columns in the past with 10,000 points. A lot depends on the quality of the posts too. Example: https://www.kidzsearch.com/questions/26724/yes-omg-10-00-points-can-i-have-my-own-advice-colum-now-lollypopqueens-type-show-i-can-see-it-now?show=26724#q26724
5,000 points are enough for a personal blog.