Value of mint condition first pressing of Sgt. Pepper?


I have a mint condition first pressing (I think) copy of Sgt. Pepper's Lonely Hearts Club Band.  Vinyl is shiny and plays flawlessly, jacket is shiny with few indentations, and insert looks like new.  Any idea how much it might be worth.  Also, any idea as to how much value something like this gains over the years?  I'm thinking of giving it to my granddaughter (age 4) for her to cash in when she graduates high school.
Any input will be greatly valued.Russ
rustler
@gpgr4blu If you search for the album title from the Discogs main page, the first result that will come up is "all versions".  Click on that and the next page will show the track list of the album and below that, a list of all releases of the album. 

Below the track list and at the top right of the list of releases you'll see a box with a magnifying glass that says "Find Your Version".  Click on that and you can put the catalog number in to narrow down the results. 

I find that going to the dead wax and putting in as much information from there as you can narrows things down even further.  Usually there are photos of the album cover and labels, so you can compare to yours and see if they match, along with the pressing info in the dead wax.
I have a related question. Where can you find the criteria for determining if an LP is Very Good, Near Mint, Mint, etc.? I have lots of old records that I would like to find good homes for but definitely wouldn’t want to misrepresent anything.