... last couple posts beat me to it while I was type'n.
Yes and no.. but mostly no. 
I like the way New Vegas did it. It let you play a bit, do a few missions in Goodsprings. Making sure to have these missions show you various mechanics and how your build can affect the outcome. Like when your rounding up help before Joe Cobb attacks, it shows you examples of skill checks: Speech, sneak, explosives, barter, and medicine. Then once you have a feel for the game, as your leave Goodsprings it essentially asks: Did that play the way you expected? If not here's your chance to rebuild your character before you continue.
But I wouldn't really care for something mid-game to re-roll a character.. that's what the New Game option is for. 