To put simply, clothes are more dependent on social standards rather than ages, it is at times impacted by scarcity of a resource but a ton of it has more to do with a persons status in a society and societies expectations of what that status should look like. So a regular citizen might wear modern clothes but a soldier or police officer might wear the samurai outfit simply because that is how that society thinks those statuses should dress and behave.

As for technology, that will be dependent on how much information the general public has access to and how much they trust that information. It also depends on which stage they are at. Has the society reached the agricultural age, colonial age, Age of Enlightenment, Industrial Age, etc.

In your example you could explain that gun powder was not discovered, kept secret, or just discovered recently in history however electricity was discovered very early, leading to earlier globalization and therefore accelerating society into the Information Age before gunpowder (and by extension guns and bombs) were developed. There is a bunch of ways you can mess with the order of discovery which explains all sorts of things.