Error on MIT application after submission

I made a mistake on the high school section, I’ve gone to three high schools, in the application they tell you to list the date of graduation, so I though that just meant the date you left the high school. I did that but when I went back to look, I accidentally put the same date of application for two out of three of the high schools. So it look like this

05/2018
05/2016
05/2016

Instead of

05/2018
05/2017
05/2016

Also, another thing is now I’m wondering as to whether I was only suppose to put one high school or all three.

So should I email mit saying that ‘I made a mistake and accidentally put 05/2016 instead of 05/2017 for (insert high school here)’ or should I say ‘I thought I was suppose to put all of my high schools, and ending up thinking that the date of graduation was suppose to be the date that you left the school’

I don’t want to email them twice.

You need to list all three schools. If the app asks for date of graduation, you should input May 2018. If the app asks for date that you left, you should e-mail admissions to correct the year. In either case, you’ll have to send a message. It’s not a big deal.