Not too old....
You are not too old. Indeed your experience would be welcome. There are no changes (as far as I am aware) on the regulatory front as far as the FI regs are concerned. Although BEagle may enlighten you on this as he has been asking for a career path for FIs that is intended to avoid superfluous work on exams with questions largely unrelated to that job. They are looking at the PPL-IR exams at the moment but no movement on the CPL.
You would have at the moment to do the CPL writtens the CPL flight test and course and the FI flight test and course. I assume you would want payment.