The event is happening in the future, so I think you're wrong. This is not something that's in the near future, when Russian present acts like English continuous.
The problem here is that Duo has used the wrong English verb - the English should be "we will be leaving" or maybe even "we are going to leave". But then, English idiom recognizes that the speaker is addressing a future event, so you have to know English idiom before you can accurately translate into Russian, which I think is unfair to non-English-speakers using this course because there is no Russian course in their own language. The exercise needs to be changed to be much more accurate.
Джеф, он прав. В русском языке будущее можно выражать с помощью настоящего времени. Я, правда, мало что понял из твоего коммента. Но факт остаётся фактом: Аркадий прав.
The English verb is right, but the tense is wrong. In Russian, we say уезжаем in reference to the future when the event has been arranged (seats booked, appointment made etc.) and we are dead sure it will happen. Мы уедем matches with “we will leave” if it’s a promise or threat or on-the-spot decision, or with “we are going to leave” if we communicate an earlier decision / plan. “We will be leaving on the 11th” requires putting the date in the beginning of the Russian sentence: «11-го мы уезжаем/уедем». In this case, the imperfective verb and its perfective counterpart are interchangeable.
Not good English idiom. That format is only used in rare instances, where the time is precise, according to a set schedule: We go on the eleventh without any delay.
Why does it just use genitive case instead of using Мы уедем в 11 июня? it confuses me a bit
The implication is «мы уедем [в течение] одиннадцатого [дня] июня» = “we will leave [in the duration of = during] the 11th [day] of June”
I've already reported this for multiple exercises over the las several months, but I just want to make sure the mods are aware that numbers are not being recognized properly in speaking exercises. This is almost certainly because the speech recognition is rendering the numbers as numerals rather than words. Is there any way for the mods to file a bug report with the developers? Alternatively we could add variants of the answers with numerals as acceptable answers.
I think that's alright in everyday Russian, but Duolingo prefers you to write out the whole number instead of just the digits. Just to make sure you know how to say the number.