I'm not sure where you are from - check your country details on the dvselectee site under "reciprocity by country". Most countries just require that you take the documents with you, but there are a couple that require them to be sent to the consulate beforehand.
Your high school diploma is all you need, and you must take it, but it may be worthwhile taking a copy of your student status with. Just in case the consular officer wants a bit more reassurance about your potential to support yourself in the US
I am from Kosovo, i think i have to take the documents with me and not to send before the interview, although i couldn't find anything on "reciprocity by country".