BTC made correction so , is it right time to buy altcoin

yeah, for sure. Bitcoin corrected more than 12% in 2 days and the altcoins were in a sea of blood. But do not panic and Fud about Bitcoin, instead of Fud, you should buy more altcoins top and hold it.
Especially with Ethereum, December will be a glorious month for it when Ethereum 2.0 launches. So the price will go up, my guess is about 700 $ at the end of the year.