Stay between leaving a school and entering another illegal, if not enrol?

I was holding F-1 visa when studying in a university. I got my master degree and then spent two more years to study for PhD. Because I didn’t pass the PhD qualify exam, I left the university, and had my SEVIS number transfered to a local community college on Sept 15th. The community college has mailed a new I-20 to me recently, though I haven’t received it and signed it yet. Since the fall semester of the community college started at the end of August, so I got admission to the spring semeseter started in Jan, 2014.

I now still stay in the U.S., because the gap between the time when I left my previous university and the time when I will enrol into the community college is less than five months.

However, in Jan 2014 when the spring semester starts in the communicty college, I may choose not to enrol because of the following reasons:

  1. if I get admission from another better university for spring 2014, I may go to that university instead of the community college;
  2. if I find a job with noncap H1b, I may go to work instead of studying in the community college;
  3. if I decide to go back to my home country, I will not study at the community college.

My questions are:

  1. If I don’t enrol into the communicty college in Jan 2014 because of any of the above three reasons, will my stay in the U.S. between Sep 15th, 2013 and Jan, 2014 be illegal?
    Will it have negative influence on my leaving and reentering the U.S., applying for OPT, H1B, and Green Card in the future?

  2. If it is illegal, how long can I stay in the U.S. after I left my previous university on Sept 15th? Is it within 60 days after Sept 15th?

Thanks in advance!

If you stay in US without taking atleast 6 credits you are out of status.

Thanks. Does out of status mean my stay is illegal? What about the three possibilities that I will not attend the community school in Jan, 2014?

If you are in US on F1 you need to be enrolled atleast 6 credits per/semester. Otherwise you are accumulating out of status ( which is illegal). More than 180 days means 3 year ban from entering US. More than 365 days out of status means 10 year ban on entry in US. you will jeopardize your future in US
Contact a immigration lawyer in such a case!