Is scratching an age spot off bad?

Possibly. You may possibly cause scarring by scratching off a lesion. Another problem is if you want to have a definitive diagnosis of whether or not the lesion is a skin cancer, you would need to have the lesion present for the doctor to evaluate and biopsy.
Better options exist. Scratching off an age spot will likely leave a scar that may be more noticeable than the original lesion. Better options to improve or resolve age spots include liquid nitrogen, chemical or laser peels, laser resurfacing and of course the daily use of an antioxidant sunscreen.
No, but... ...It will usually grow back. A dermatologist can freeze your "marks of maturity" with liquid nitrogen to remove them permanently.