I can't tell from your post what the car is. But, Ford coil springs will sag with age. I discovered this on my '90 LX when it could no longer be aligned, so I replaced the springs at that fixed it.
Assuming there is no prior body damage - I’d check that the tire pressure / wheels are exactly the same, that there is no weight in the passenger compartment / truck that would affect the ride height, and then I would park and measure in a different parking spot that was level. If the simple things check out - I’d check the front spring isolators and springs. Springs are the primary determinant of ride height.
My ride height was a little off recently - took my front suspension apart and replaced my spring isolators, they were 10 years old and literally crumbled in my hands as I took them out. Ride height fixed.
If your looking at it anyways why not upgrade. I just installed a set of SR lowering springs from American muscle and it’s a big difference in both looks and handling. Plus it’s not hard to do the work yourself with some simple tools