I unfortunately did not get the course I was hoping for in first round and only got my 4th choice which I'm not too sure about. I don't think I will get decent offer in 2nd round, should I go ahead and accept 4th choice as I dont want to repeat?
I wouldn't do this unless you're sure that you'll stick with it. I took a course I was not sure about and ended up dropping out in April the following year. I could not re-enter CAO as would have had to pay all costs 2nd time. Even taking a year out and reapplying next year for a course that will match your points and that you'll be more likely to stick with would be a better option, or you could do a one year plc course which might offer an alternative route into a better cao course if you do well enough in the exams at end of year..