What should i do this old man always stares at me when i run?

i always run past the school everyday and this old man always stares and looks up and down, it always makes me so mad and unconfomtroble i always ware short shorts alot, but im not wearing long pants it is so hot out. i ussuley ignore him one time i flicked him off i was so mad but then i felt bad but not like he saw it lol all well. so should i ignore him? it makes me mad lol.