If I sign up for membership after playing games for say, a few weeks, will my stats page reflect that or only the games I've played while owning a valid membership.
The site keeps track of your stats from your very first game onwards. As a non-member you just can't view them (the full stats anyway). So to answer your question: you'll see your stats for all games, even those you played before signing up for a membership.
If I sign up for membership after playing games for say, a few weeks, will my stats page reflect that or only the games I've played while owning a valid membership.