Ascii Tree Art

[beepBoop123]

Hi, I'm trying to create a function that will make the correct sized ascii Christmas tree art based on the size passed in. This is what I have so far

def get_festive(size):
    Triangle = ""
    for i in range (size+4):
        Triangle += ("*"*((i*4)+1)).center(((size*4))," ")
        Triangle += "\n"
    return Triangle

This is what I need it to look like:

get_festive(3)

          *
        *****
      *********
    *************
        *****
      *********
    *************
  *****************
      *********
    *************
  *****************
********************* 

This is what I have so far:

get_festive(3)

     *      
   *****    
 *********  
*************
*****************
*********************
*************************

Any suggestions or if you know what to fix let me know - thank you!