So, barring someone’s putting something silly on your tombstone, do you hope for a comment similar to that placed on Wren’s marker?
Not an architect? Haven't so much as designed a tool shed? True, buildings do last a long time, but all of them eventually fall into ruin to some degree, and some purposefully so—before Wren’s edifice arose, the previous “cathedrals” on the site had been damaged or destroyed by both foreign and domestic political and religious groups.
Maybe “look around you” can be a reference to the lives you touched. Maybe those are your monument. They might not last as long as a large building, but they will be conscious of your role as architect, unlike the cold stone of a church.
Don’t know if you’ve built any such monuments to date? Then it’s time to start laying the cornerstones.