I came across a SAP Consultant who started his career after 45 years.
Right move or not depends on many things to be considered.
Definitely your functional experience would be useful....If you learn any new SAP Functional module, you would be still be a new person in SAP and salary might not be that great in the starting. You need to work in atleast 2 end to end SAP projects to gain good experience.
You need to decide whether its worth the risk at 45 years.
You need to consider your present job, family, obligations and all and then take a decision.
All the Best.
The "black and white" answer is that it is not the right move.
Ofcourse, there are exceptions...but few and far between.
Are you ready to "struggle" for the next 5 to 10 years? (hard work, long hours, *hitty work, conflict with SAP "consultants" who know less than you but don't listen, less money etc.)