Other translations used the word "محددة" as a translation for the word "selected" here and that's correct but I think that using "الذي اخترته" which literally means "that you have chosen" sounds more natural in Arabic and it's better than translating word for word.
Another point is that when {count} is one or two then "{count} selected day" or "{count} selected days" can be tranlated without using {count}, for example "two days" in English means "يومين" in Arabic. As you can see it's 2 words in English and one word in Arabic, so not including {count} wasn't a mistake when it's one or two and it sounds more natural in Arabic in my opinion.