Please help me, I am trying to understand a pattern.


I am learning how to crochet, and I am trying a project, but I am not sure if I understood the instructions, mainly the Row 2. This is part of the instructions:
Body Ch  109  (123,  137).
Row  1  (Right  Side):  Dc  in  4th  ch  from  hook,  dc  in  next  ch   and  in  each  ch  across;  turn  –  107  (121,  135)  sts.
Row  2: Ch 3, skip first dc, dc in next dc, and in each dc across,  dc  in  top  of  ch-­3;  turn.
Repeat  Row  2  until  20  (22,  24)”  from  beginning.  Fasten  off.

My questions is: does this mean that I should decrease or I always keep the same size? That is, when I finish the body, it should have 121sts as it has in the beginning or less?

I will copy and paste one more part of the pattern, in case you need more information:
Side  Seams
Fold  Body  in  half  with  right  sides  together  so  that  piece  is   now  10  (11,  12)”  high  x  32  (36,  40)”  wide.  Sew  side  seams   from  bottom  corners  toward  fold  line  through  12  (14,  15)   sc  of  both  thicknesses  leaving  40  (40,  45)  sc  free  for  each   Sleeve  opening.

Thank you!