8老师您好! 想向您咨询一下绿卡移民的问题。我几年前给在国内的姐姐一家申请了绿卡移民, 前段时间收到了NVC的notice of immigrant visa case creation letter， 里面通知NVC received your approved immigrant visa petition from USCIS. 但我用NVC case number 登录到NVC 网站后, 收到以下summary information :
Due to the numerical limitations on immigrant visa issuance prescribed by law, this petition is not eligible for further processing at this time. The National Visa Center (NVC) will retain the petition until an immigrant visa becomes available. The NVC will notify the petitioner, principal applicant, or attorney of record when this petition is eligible for further processing. The principal applicant should not make any firm plans such as disposing of property，giving up jobs, or making travel arrangements at this time.
请问这是什么意思呀？我收到的NVC通知是指绿卡批准了吗？到NVC后为何又不eligible呢？当时申请时姐姐的孩子还不满21岁, 但今年刚刚超过年龄，会是这个原因吗？现在是不是应该把孩子的取消? 一般收到NVC case creation后下一步应该是什么? 会多长时间呢？
抱歉问了很多问题, 很多年前提交的绿卡申请，但对之后的步骤和要求完全不懂,网上查有关兄弟姐妹的绿卡内容也不多,没搞懂流程, 非常感谢您的答疑和帮助!!!