A Little Help Please

Hopefully this is a good spot to post this.  I happened to stumble across this site when I was looking for ring information and it looks like a lot of good people with some good posts so here I go.

I need some advice/opinions from a female point of view and I can’t ask most my female friends because they are friends with my girlfriend and I want this to be a complete surprise so it really limits who I can ask.  Hopefully I can summarize this without writing a book.

My girlfriend and I have known each other for about 10 year and have been dating for about 2 years.  A few months ago we started talking about getting married and decided to go to premarital counseling  to make sure all of our ducks were in a row (will be 2nd marriage for both and we both have kids so we want to make sure we do it right and it is forever).  At this point I have never officially proposed and we haven’t even gone to look at rings but I want to make it official so last week, without her knowing, I went and looked at engagement rings.  I had no intention of buying a ring and was just looking to get an idea of styles, but I ended up finding a ring that I couldn’t put down, beautiful natural yellow diamond at the top with white diamonds under it and leading up the side to it.  The only thing she has ever said about rings is that she wanted a yellow diamond and was different than the standard rings that are out there and this (IMHO) fit both of those criteria perfectly.

Now that all that is out there, here is my dilemma….The ring is too small and I’m not 100% of her size.  I thought she was about a 7.5 (based on some shopping trips I have accompanied her on), but a couple of people that I did tell didn’t think that was possible because she has a fairly small frame and they guessed more of a 6.  A couple days ago I snuck a couple rings out of her house and had them sized and one was a 7.5 and the other was 7.75, so I felt good about the 7.5 I originally thought.  But then I was told there can be a full size difference between the left and right ring fingers and I’m not sure if she has ever worn these rings on her left hand (she doesn’t wear her rings very often).  I came up with a story to ask her for her ring size without it being suspicious and it worked great….but she told me she wasn’t even sure….she thought maybe a 7.5, but she also thought it might even be an 8 because she has big knuckles for her size (so she says).

So my question is this.  Should I go with my gut and just get it sized at a 7.5 or should I wait until after I officially propose and have her sized?  I would like for her to be able to have the ring as soon as she sees it and not have to wait until we get her sized and then have the ring resized.  If you were being proposed to would you want to wait to get the ring?  Also, will it cause any structural problems to have it sized 2 times if 7.5 ends up being wrong?

Sorry so long but this is stressing me out a little because I really want this to be a complete surprise and right now she doesn’t even think I have thought about getting her a ring.

Any input would be appreciated.

Unfortunately, she is a very light sleeper so I couldn’t get away with that and I don’t trust any of her close friends to take her to the mall without the whole thing slipping out.  I think I will just go with the 7.5 and keep my fingers crossed.  Thanks very much for the feedback.

Will get a few pics up.