The Latics are currently in 12th place in the table, but they can climb into the playoff places if they win their two games in hand.
"The Championship is a very, very tough league," Whelan told Sky Sports News. "It's a very good league; there are a lot of good football teams in there and they play for 90 minutes non-stop.
"I'm happy with how things are going. We've got two games in hand, of course, because we've got to play in Europe.
"If we can get points out of those two games we can go into the top six, so I'm very happy with the way things are going and how things have started."
Wigan continue their bid for promotion on Saturday when they face Blackpool at Bloomfield Road.