George Lucas is no longer a part of Lucasfilm, and is not involved with The Force Awakens beyond a story credit, so his first time seeing The Force Awakens was apparently much like any moviegoer’s experience; mystery and excitement. The only difference is that he created the universe that the movie inhabits.
According to Kathleen Kennedy, he ended up liking the movie – and George himself said the following when asked about it:
“I think the fans are going to love it. It’s very much the kind of movie they’ve been looking for.”
Some might consider this remark “damning with faint praise”, but it seems that he really does like the movie, and, possibly more importantly, says that audiences will as well.
While some seem very cynical about George Lucas’s opinion of The Force Awakens, there is no reason to suspect that he is being insincere about liking the movie, so it seems that he has given it his seal of approval.