Prelay shed

My female is in the early stages of shed her belly is slowly becoming a creamy pink but I believe this to be her pre lay shed she has ovulated and shown many signs I can feel about 4 egg shapes in her belly when I palpate her feel quite a bit different from when she was building follicles she is no longer as big as she was in ovulation and I know she might not shed for a bit now since she's just starting to go pink but when should I start my prelay shed countdown after she has shed 100%?

Yes, countdown begins when she actually sheds not when she is starting to.

It's termed post ovulation shed because its alot closer to it. Females can lay 27-50+ days after that shed. Some have even experienced two sheds after ovulation.