Sir, my neet score 488,AIR 26262 and was my first attempt.I won't be getting admn in any govt med clg.shall i repeat or join private clg ?

Well. It should be your own decision. You have actually scored very good. I am surprised why aren't you getting a government college. I think, at this score you might be able to get a seat in state quota.
Nevertheless, let's come to the point, see, one should drop an year only when he/she is sure that next year he/she will perform much better. Since, cutoffs generally rise each year, so it is always advisable to drop only if one can score considerably higher. But, like I already said, you have scored good, so I think it won't be a bad decision to drop an year. If I were at your place, I would have definitely gone for a repeat.
I advise you to think alone about all the aspects and then arrive to a check conclusion.
All the best.