is your fat percentage average if you're around 5"6 or 5"5 and weight 145lbs?

Answer 1

you cant tell body fat percentage just knowing your height and weight - ask dietitian or at the gym to measure it for you.
you can weight a lot but have low body fat percentage - e.g. bodybuilders - and their bmi's can even say they are obese (thats why weight and bmi are pretty irrelevant numbers)
or you can weight very little but have relatively high body fat percentage (people with eating disorders usually have that because they lose a lot of muscle)

Answer 2

That depends on your body frame and how much muscle you've got. You can't tell just from weight and height.