Since you have decided to remove the popcorn yourself, please be aware that it is a complete mess and in most cases you need to mask off all the floors and walls with plastic and your fixtures with paper or plastic.   If you don’t do this, be prepared to be cleaning for weeks.  Make sure after you remove your popcorn that you change your air filter from your ac unit because it will become very dirty from all the dust.

Masking of a room from walls to floors

Popcorn makes a big mess