I'd argue it's not ambiguous: current age would have to be a function of invocation time, while "age at time of writing the function" would be a constant.
Expressing "age" in whole years is acceptable in English, but using a decimal would be highly defensible. That's an issue of grading though.
Yea, that would have stumped me, expecting a trick/trap. What if my birthday is tomorrow? By the time my teacher checks it, it's wrong. "Your birth year" would have prevented that.
This is a problem I have with certain parts of computer science and math education. Everything is encouraged to be exact, then, suddenly, variable names are used inconsistently, niche cases are ignored arbitrarily and explained with essentially referring to "common sense".
It's graded immediately (automatically), so there wouldn't be any issues. Further, the text of the problem makes it clear that I'm not actually going to check their age - they can return any valid number (although it does check >0 and <100, perhaps discriminatorily). It would be a little invasive to their privacy otherwise, I think.
But general purpose education isn’t „the real world“. I think the opposite argument is often made to justify teaching theory when it doesn’t seem to have many real world applications.
If we were talking about pure functions, I would certainly agree, but in Python it would of course be perfectly fine and not unusual to have an impure function implicitly depending on the current time. Obviously assuming »consume nothing« only refers to the parameters of the function, so this too could be less ambiguous.
Expressing "age" in whole years is acceptable in English, but using a decimal would be highly defensible. That's an issue of grading though.