关于OPT所需的时间

我目前收到一个公司的offer，要在7月20日入职，但我OPT received date是5.1，想问一下大家不出意外的话在7/20前能收到EAD吗，需要和HR协商入职时间吗，谢谢！现在很后悔没早一个月申请= =

补充内容 (2015-6-24 11:24):
6/16 was approved
6/18 was mailed to me
6/23 received the card