I think the sentence is fine. There should be some humor in the course. Besides, it is very common for medal winners to bite their medal to make sure that it's real, hahaha. Serious question for the native Korean speakers, in Korean is eating the medal the same as English biting the medal? Or here is it literally eating?
On the contrary, Pam. Korea and its humility culture do seem to encourage the use of those deferential forms, ~아/어요 and ~ㅂ/습니다 to show respect to the listener(s), with the latter (the 요) being more casual/ intimate.
• The other 2 forms:
~ㄴ/는다 - plain/impersonal form is used mainly by media
~아/어 puts the speaker(s) somewhat in a position of authority. That is why it is often described as to be used when speaking to people younger, children ...
• Don't mix those verb endings (speech levels) with the "Honorifics". The Honorifics are terms of reference reflecting the relationship between the speaker and the subject of the conversation ("not" necessarily subject of the sentence). Subject of the conversation is sometimes referred to as 3rd party (to distinguish it from the Speaker and Listener).
I' ve heard medals have only golden and silver coverage and they are not really made of these metals))) but champions still bite them just for fun))) I do love Duolingo for its humour, because there may not be love without a smile))) it makes me laugh every day and my passion for studying grows=))',