Saucer sighting

UFO Report  I don't know the exact date this happened.  I know it was in the springtime and I think it was in 1970 or 1971.  I was in the fourth or fifth grade, that much I do know.  It happened in La Grange, Il., a western suburb of Chicago.  Because of the uncertainty of the date this event happened on, I am hesitant to report this, but I heard a plea to report any sightings to see if they could be correlated and so decided to go ahead and report it recalling any detail I could remember.
It was after school, so in the mid afternoon around 3:30 pm, probably DST. I recall it was a pleasant temperature. The sky was mostly sunny, but there were large fluffy clouds in maybe twenty to thirty percent of the sky. I was cutting through an empty field at the corner of Elm and La Grange road which I always did when I was that age. Now there's a public park at that corner. I liked to look up at the sky. I remember that the sky seemed so blue back then. It seems to me that the sky was bluer back then, but who knows?  Anyway, I looked up and I saw what I would describe as a classic saucer shaped metallic object hovering over my head at about the two o'clock position. It was shiny and obviously metallic. I would estimate that it was maybe 1500 to 2000 feet up, though I wouldn't have known that back then so it is my adult knowledge making that guess. It looked like it was spinning on the outside. I just looked at it for a few seconds, kind of amazed I was looking at this thing and wondering if it saw me. It was between clouds, not even close to an edge. I remember the clouds were moving slowly in the sky but this thing remained perfectly still for at least 10 to 20 seconds. I just stood there and stared for that amount of time, then suddenly in a streak that shot off to the southwest it was gone. It just kind of disappeared in that direction in what I would guess was less than a second. I then focused my attention to my front and went home. I don't remember experiencing any lost time.
I never told anyone about this experience. It is the only time I can recall seeing a UFO in the daytime. I don't think it was anything that could be explained as a natural phenomenon, but it could have been a manmade thing. Anyway, that's my report. I apologize that it's not very detailed, but it happened so long ago. I didn't want to tell anyone back then because I knew it wouldn't be believed, but it is something that has stuck with me all this time. Thanks for the opportunity to tell someone and I hope this helps someohow.
Witness indicates that the date is approximate.  PD