NEW YORK (Reuters) – Late night talk show host Jimmy Fallon, who will take over from Jay Leno as the host of NBC's "Tonight" show next year, said he and his wife have had their first child, a girl. Fallon's wife, producer Nancy Juvonen, gave birth early on Tuesday morning. "My wife and I thank you for all for the nice baby well wishes. Her first day was the best day of our lives. So happy," Fallon said on Twitter on Wednesday. The 38-year-old comedian, who is the host of "Late Night with Jimmy Fallon," started out on the long-running "Saturday Night Live" comedy show in 1998. …