While Japan would be a fantastic experience, California would be INCREDIBLY cheaper in terms of travel and a lot easier to save for.
Plus the issues with Japan of having to acquire a passport if you do not already have one ($100 regular fee, $160 for expedited service, plus you have to pay for your passport photos, which usually run $15), exchanging currency, and language barriers, etc.
If all you're looking to do it shop and want the experience of actually being in the shop, go to California. There's also a store in New York that sells some Baby items, even though it's not actually a Baby store. Heck, if all you want to do is buy clothes, you can do that easily online and save the travel costs altogether. Japan would be more culturally enriching, and would provide opportunities to go to other stores than Baby, but it would also be more of a hassle. Up to you what you would like to do, and the biggest question would really be to ask yourself what you want out of the trip.
Vivienne Valentine
I hear the airplane trip to Japan can be 24 hours!
Flight time from Texas to San Francisco and then from San Francisco to China, which is clearly farther than Japan: was about 15 and a half hours. The flights home were shorter and totalled up to 14 hours.
When you take into account layovers, both trips were about 17 hours.
The only time a person in the US is looking at a potentially 24 hour flight or longer is if they're going to Australia or New Zealand. Those flights are a real pain. But from the US to China or Japan, 17 hours is a good estimate.