If you must apply for a community college, it will take four years to complete a complete undergraduate course. If you apply for postgraduate courses, you will waste too much time. You can apply for postgraduate courses directly, and the entrance requirements are not high. And you already have an American green card, and the employment pressure is much less than that of international students. You can also take the 1-2-year certificate postgraduate course directly.
I wish you success and welcome questions.