Doubt on X2 Visa

My nationality is Brazilian, but I live in America (I'm not a resident though) to study and I was awarded a scholarship to study in China for a month. I was instructed to get a X2 type, since I'll be studying in PRC for less than 180 days. My program starts June the 25th of 2016, but my doubt is: would I be able to enter mainland PRC about a week before? I have a friend that I wanted to visit and I would stay in her house before my program starts. I'm about to purchase my airplane tickets, but I'm not sure about how early I would be able to arrive to PRC if my program starts June 25th.