Duolingo suggests "She is 20 1 years old" instead of "she is 21 years old."
Whoa :D By "suggest" you mean hints when hovering over a word? I see only words.
No. If I write translation as "She is 21 years old" it does not accept it as a correct one, instead it says that correct way would be "She is twenty one years old" OR "She is 20 1 years old".
AHAHHAH really :D
OK, this is some general Duolingo glitch, not particularly Ukrainian Duolingo.
I added "twenty-one" to the first sentence, now "21" is accepted! Thank you for the comment!