Anyone who hasn't play FFL in the past should first play in a "free" fantasy football league (Yahoo, Sportsline, ESPN) to get a feel for how the play works from draft through head to head games. Get a feel for the game, and come back next year. Or find an experienced partner who can guide you through the season as an advisor.
There is a weekly commitment to maintain your team by upgrading off the waiver wire or negotiating trades and setting your starting lineup each week. If you don't maintain your team and start non-active players, then the quality of the league is severely degraded and it sometimes allows other teams to win unfairly (especially if they draw a team with an inactive owner at the end of the season during crunch time with playoffs approaching). The FFL season is far more fun with everybody giving their best effort to remain competitive through the season and playoffs.
That being said, anyone who is ready to play should definitely sign up. I will have no problems taking your money.