60 yard dash Question


As you may know, i’m 20 years old when I was 17 (and i used to be a fulltime outfielder) i used to ran 7.25 on 60 yard dash my weight used to be 155 lbs, but now i gained muscle mass and my weight is 170 lbs i became slow now i can’t make times under 7.55.
Is this normal or its just a circumstancial thing? Is it too late to attempt to make a under 7 seconds time?