and though it's preferable to use "their" tableware in the restaurant, none will care about your using your own knife and forks when in a casual restaurant.

I say this because I had a couple friends that were also concerned, but once I taught them how to use chopsticks they were thrilled to be able to use them while in Japan as it was part of the dining experience.

Carrying your own travel cutlery is a good idea if you plan to go to small noodle restaurants and really can't manage the chopsticks. Keep practicing though, most adults pick up the skill fairly quickly.