Sources on the show tell us contestants and crew working Clare Crawley's upcoming season were supposed to get into full filming Friday, but that has been delayed. We're told they hope to start things up on Sunday ... but that's not for sure yet.

38-year-old Crawley is the show's oldest star to date ... and was officially intro'd during the season finale of Peter Weber's season earlier this week.

Crawley likely won't mind pushing her start back if it means staying healthy and finding a better partner than Peter did. Weber first broke off his engagement to Hannah Ann Sluss before announcing he wanted to rekindle things with show runner-up Madison Prewett.

However, he and Prewett announced Thursday they were no longer going to try to make things work.