My "student" needs help!

Hi Everyone!
You may remember me saying that i was going to teach my left handed friend how to knit. Well i did and she’s doing GREAT!! She’s almost done her hat and will be ready to decrease soon. My problem is that i always decrease to quickly. Could anyone give us a good guideline as to how far she should knit before starting the crown shaping? And please let me know what you would do for a 120 stitch count gradual decrease. She doesnt’ want it to pucker at the top she wants it fitted and smooth.
THanks everyone! My friend will be on here soon herself under the name “LEFTLOOPER” looks for her! Thanks so much in advance.:woot:

Here ya go,this will do it for you

Wow. That’s crazy. Thanks a lot! She already has about five inches of knitting done. By the looks of this chart do you think i should tell her to stop and start the shaping?