Hi J.,
I took my daughter to Europe when she was 5 months old and like you I was anxious about it too. It was a piece of cake.. my daughter adjusted so well it was unbelieveable. Babies at that age are so flexible and adjustable, they are quite impressive. My daughter in fact slept better overseas than she did at home, I think it was the cooler climate and the cloudy skies of Ireland that did it for her !!
With regards to the time difference, I didn't really do anything specific. I just kept up with her naps and the rest fell into place. Try not to worry, you may be pleasantly surprised and remember you can't control this kind of thing anyway. Relax and enjoy your trip. You could also try a little bit of children's benadryl, it may help your baby sleep on the plane, but make sure you give a few "test" doses before your trip to make sure it's tolerated ok. Also, remember to feed her for take off and landing to minimize any discomfort due to take off and landing.
Good luck and have a great trip and remember, you may be worrying over nothing.