1. They can remove you from the company and report to the police or appropriate authorities.
2. They can remove you and have you black listed on the data base for future, and penalize you financially (Reimbursement of your salary this depends on the company you work for)
3. They can remove you and do nothing. (This might be just what you want).
Having fake documents is always a risk, its illegal, immoral and unethical.
When you know its wrong why bother doing it ? It might take sometime to finish college but you will at least gain some knowledge and get a real certificate when you complete it.
Not sure what career path you plan to choose in future, but I wish you all the best and hope you find the job that you are looking for.