As far as i know, the system counts your activities: comments, likes, posts, etc and at certain numbers, you’ll be leveled up. If it “keep changing”, most likely youre really active here 😄😄. Anyway, congratulation on your leveling up!

You have a very long way to go! I fought so hard to get myself a rooftop apartment!

Queen @sicarius is who you should ask.

No one really know how it works, but it is related to how the number of your posts, people you follow and followers you have as well as the how many posts/ comments you like. Keep in mind that it seems that comments on recaps have more value than posts in the beanie wall.
Here you have a link to Sicarius list of Beanie Levels so you can get the references: https://docs.google.com/document/d/1SsqpfZ2762NF6MDwHQRHj4s2yQhaiOQkaTpn26Ty78o/edit

WoOOooOOooo it is a very great secret *wiggles eyebrows vigorously * 😯 The more active you are, the faster you will move. Until one day you will become an Errand Boy 🛵 and you will run errands for years, or what feels like years. Finally you will achieve Rooftop Room Dweller, yay! And we will throw you a party 🎉🎉🎉 I don’t know what happens after that as I love my rooftop and have vowed to never leave 😉

Thank you for all the responses. They were really helpful.

Ahem, you already have several answers, however, I have written a Field Guide to the Beanie Levels which you can peruse here:
https://www.dramabeans.com/members/sicarius/activity/1082872/