Translation:My teacher is a bit scary.
怖い and 可愛い sound so similar but their meanings are worlds apart.
goes to show that bad pronunciation will lead to awkward conversations. ( ͡° ͜ʖ ͡°)
My teachers but not My teacher. You know, my school life was not that bad Lol
"My teacher is quite scary" was not accepted? Using a bit sounds a little childish
"Quite" indicates a high level of something. "A bit" indicates a low level or amount of something. In thus case, the teacher is only a little scary. Quite (very) would be ほんとうに or とても.
Instead of "a bit", you could try "a little", "somewhat", "slightly". Duolingo accepts "a little" but not the other two. Is there any reason すこし couldn't be translated as "somewhat" or "slightly"?
Seems like a reasonable translation if you speak British English. In America "quite" is the opposite of the British, meaning that the teacher was very scary.