Yes you can join another college but you will have to repeat the entrance exam as well you will have to repeat the first year. Because I've seen people who get a private college in the first year and then they prepare hard for the entrance examination and then give their best and secure a seat in some better college. But all you need to do is repeat the first year as well. But anyhow if you are getting a good college that's absolutely okay I guess. 

Best wishes.. Thank you.