Yeah, YABU.
My dd has no concept of time. Anything in the past, even if it was last year is "yesterday" and everything in the future is "tomorrow" she doesnt understand how long a day is etc..
She does however, understand "how many sleeps", if we say we're doing something/ going somewhere etc.. she'll just ask how many sleeps. Most adults in our family use it now because of her.
Dont think its a big deal tbh, if it helps a small child understand time who really cares?