Thank you for your help, @leonhard.wettengmx.n. I read the direct links you recommended as well as all the others listed on the homepage I thought I'd understand.
In the code convention page, I saw this on names:
Names should be formed from the 26 upper and lower case letters (A .. Z, a .. z), the 10 digits (0 .. 9), and _ underbar....
I didn't see anything about underscores vs camelCase, and both Crockford's survey page and MDN's object page seem to use one-word names* for object keys. I did see this recommendation on Google's JS Style Guide:
In general, use functionNamesLikeThis, variableNamesLikeThis, [...] methodNamesLikeThis...
Although they also do not name keys specifically (do keys count as a type of variable?) they do mention methods, which are a type of key(?), so from this I infer that camelCase is convention in keys, too...?
*I was on the lookout for this until the very end of the JS track, but alas, all other keys in the lessons were single-word keys, too.
I also didn't see anything about spaces in keys, but in the MDN link you recommended me in another answer I did see this:
From this I gather that my property key can have a space, but infer this is best left to dynamically determined keys, whereas ones I make in advance are best be written in camelCase and without spaces(?).
Aside: Therefore I would guess in retrospect that I couldn't log "age age" because I can't use dot notation, which iirc I tried first out of curiosity, and because I most likely used bracket notation incorrectly.
In regards to having an empty string as a key name, how would I access that property? Would I have to access it using some kind of array-like syntax?
And what if my dynamically determined keys share the same name? How can I tell one from the other?