traveling overseas at 26-28 weeks

Melissa
My hubby and I booked a trip to Italy (from CA) back in January when pregnancy was not on our radar.  Well, surprise! We are expecting our first (due in early December) and at the time of our trip I will be 26-28 weeks pregnant.   
Does anyone have experience traveling like that while 28 weeks pregnant? We will be in the amalfi coast, cinque terre and Florence.  I'm very active and in good shape and am 29 years old.  I'm hoping I'll be ok but as a first time mommy I have no idea what to expect to feel like at that time.  
Any advice from those with similar experiences would be appreciated :)