FYI, the Lumix ZS100 is a 2+ year old camera. Not saying that's bad, just an FYI - it sure has terrific specs for the price, for a camera that size. I bought my Lumix DMC-FZ1000 last year knowing it too was an older model, but I bought an "open box" version on Amazon for $100 off, so at least I saved some money. (Mine had only 135 frames shot on it when I got it, so almost new.) I really love my Lumix, though it's not a "point and shoot" like this ZS100 you're looking at.
Tip: buy a spare battery (eBay for an off-market brand is all you need). Maybe even buy a spare charger. I've bought a couple of spare batteries for my Lumix that have maybe 60% the charge time as the factory battery but for maybe 1/10 the cost, and one of the spares came with a microUSB charger compatible with my Android phone charger. My Lumix original battery does not last me even the whole day of shooting when I'm traveling, so I need at least one charged spare with me.
Also, try your best to get out and try and use the camera to get used to it before your trip. Don't learn how to use it in Japan! See how it does in low light situations. My Lumix took a lot of getting used to, vs. the Canon DSLR I had used for years. The time I spent in advance shooting with it was time well spent after I finally took it to Europe.