"Look before you leap." means you shouldn't act without first considering the possible consequences or dangers. "You can't teach an old dog new tricks" means that it is challenging to teach a person something new things. Most likely that person has been doing things a certain way for so long that they're too stubborn to learn how to do it differently.
The response should indicate an awareness that a formal interpretation would focus on the structure, literary elements, and devices in the poem, while a biographical interpretation would focus on the author's life and movitations.
