Sound wisdom. I think young people lack a time perspective. The job you are doing today is not the job you will be doing forever. It is a stage and a springboard for better things.As a young guy with little experience , should he fails as DC at Florida he will get flushed back to mediocrity and most likely forgotten. The better career move at his age is to work under the best head coaches you can and pay you dues. Then when the opportunities come, and they will come, you'll be best prepared and people won't be so quick to flush you. I call it the Major Applewhite effect.
That said, if your mentor wants you as DC at a major college, that is tough to turn down.