Issaquah, WA sighting - summer 1969

It was summertime, approx. 1969 - I was 9 years old.  Me and two of my friends were were at the swimming pool in our apartments at approx. 4:00pm. A silver, not shiny, disc/saucer shaped object, very large with what appeared to be some lights flew over head.  It was going slow enough that we could tell what it was - maybe 30 MPH.  It is hard to judge the distance of height in the air - much much lower than a small airplane would fly.  I remember feeling stunned, and not quite believing what just happened.  It went towards Cougar Mountain in Issaquah.  We told my friend's older brother about it - he and a friend went up on an old dirt logging road the next day and found a spot where the brush/grass had been "flattened" in a large circular area.
I have wondered all these years if anyone else experienced this sighting in Issaquah or the Seattle area.  No one really wanted to believe us back then - who believes a 9 year old who says she's seen a UFO? I have always believed in other life out there because of this sighting and I know it's just a matter of time before the truth becomes known to this world.
Witness indicates that date of sighting is approximate.  PD