Vegas first timers there is so much to see and do. I would take her to the Bellagio fountains and Conservatory, Mirage Volcano, TI free outdoor show, Ballys Jubilee show, Ceasars Palace chocolate store go to the clock and wait for chocolate truffles to come out(free),Flamingo wildlife, If you like chinese food Venetian has the best Chinese restaurant "Noodle Asia" in my opinion order shangai rice cakes. M Resort has the best buffet, pick up the free shuttle to go there. Go to the Rio free shuttle there see the show in the sky and eat at their buffet, compete in a slot tournament at main street station, if you are downtown. Mandalay Bay buffet is very good but small. O show at bellagio is excellent. If your there on Sunday the Palms has a mexican buffet brunch. Caesars Forum Shops has an Atlantis show back by the aquarium. If you do buy show tickets buy them from the 1/2 price tickets stand, the morning of the show.
Go up to the top of the eiffel tower at night its beautiful. Have a great time. My husband and I go 2x a year and love it there.