How long would it take to shed time off my 40 yard dash?

I run a 4.9 and im aiming for 4.6. How long would it take. Heres some editional info. I lift with my legs twice a week, squats and editional workouts. Meet a sprinting coach once week to fix form and run 4 times a week, 2/4 days is resitence training(weighted sled). Just started all this about a week ago. Thankyou for answering