That's the great thing about being a metric user in the US. It's not the common system here, and the only people who really use it consistently are those who do so for work, and those who just enjoy it the same way one might enjoy learning a new language. It's sort of a grassroots thing here. And because it's not the standard system, there's no one here telling us what measures are socially acceptable to use and which aren't. Use the decimeter. Hell, if you like it, use it in Europe, you might get a weird look, but it won't be like asking for the distance to the deli in leagues. They'll still understand. In the US, use the decimeter if you want. I've used the metric system exclusively for so long, started as a sort of personal test, that I tend to think in metric now. I look at something and think "30cm" more than I think "a foot," occasionally I'll think "bout a 1/3 of a meter."

Have fun with it. Also, hot tip. If you ever struggle with temps, it's percentage of boiling. 0% of boiling is frozen. 100% of boiling is boiling. 20% of boiling is nice.