The Bluebirds beat Blackpool 3-0 at home on Saturday to maintain their 100% home record, having won four of their last five outings.
However, Mackay is refusing to get carried away going into their match with Birmingham City on Tuesday.
"There is nothing to get carried away about. We have only played eight league games," Mackay said.
"It's far too early in the season and there's far too few games have taken place to have [a] swagger.
"That's a 10-games-to-go type thing when teams are on a real roll and look as if they are on their way up."
Cardiff find themselves on 16 points at the top of the table along with Brighton & Hove Albion and Wolverhampton Wanderers.