hope all goes well and your marriage is as wonderful as mine is....we share the same values, lived independtly and both ran a household and can make and keep budgets.
my experience.....take your time
look at diamionds unmounted, mounts hide flaws. don't use a mall jewerly store- i looked at 200 loose diamonds over 3-4 months to pick the exact one....browny points for the wife...but that's the way i handle ANY jewerly purchase for my wife...i make it as personal as possible...i picked out you ring not some lacky....develop a relationship with a good certified jewler...you'll visit and trust them often
a .9, .96, 1.03 carat are nearly identical to the eye and can save money by not specifying the "actual " size, e.g don't say "i want a 1 carat, or 1/2 carat, diamond," say about that size and look at them with a loop.
the engagement ring is separate from the wedding band, i got my wife a round standard cut engagement ring and picked out AT THE SAME TIME and "wrap" that goes around the engagement ring THEN AFTER THE WEDDING GET THEM SOLDERED TOGETHER SO THEY FIT ANDDON'T SLIP AROUND.
get a simple gold band for both of you--why? we got married in the church and we had all bands blessed so i have a diamond wedding ring that she picked out for me, and my band, both blessed and i can switch them without going ringless (can't do that, i have to have a ring of wonder on me at all times--and i can wear the band even with gloves on)
get a rider on you home insurance, have it appraised (should come free) ask your insurance company which appraisal association is best....some are just junk.
size--ask girlfriends or family members, unless you can get one of her rings and draw the inside on a piece of paper and give to you jewler...make an appointment for sizing soon after you give it.
when i told my wife "i love you" on valentines day, i knew she was the one to marry...we had gone out about 12-14 months, we got engaged about 2-3 months later on a trip to san francisco but was engaged for about 4-5 months. basically you set A DATE mine was the first saturday that was the same day as our first date (more browny poins) which was the 19th, so the first 19th was in april and bingo.
sit back a feel the love.