I recently hired the services of a personal trainer. She's helped me with upper and lower body workout regimens and provided basic nutritional help.

I Jazzercise 3x a week and my question is, if I go to the gym 3x a week (in addition to the Jazzercise), when will I be able to see noticeable results?

I'm going to Las Vegas with my bf late August and I was hoping to look a little cut by then. Is that expecting too much?

It depends on your age, level of fitness, etc. If you have never lifted weights in the past and are doing it right, you should see noticable results in 4-6 weeks.