Some jurisdictions offer initial reading with a booklet like "On the Threshold". They tend to be brief summaries of Masonic history or philosophy, state activities and charities. Feel free to read all you wish on topics like that.
Avoid reading about the events of the ceremony. Do you know anyone who as a kid found their Christmas presents, opened them and spoiled the surprise? Reading about the degree is a bit like that. Go in and let it be a surprise as that increases the emotional impact. Step out in faith that your friend who sponsored you will take good care of you just as the friend who sponsored him did years ago.