Bankroll and whether your skills allow you to win in a particular game aren't very closely related IMO. You need the proper bankroll for your regular game to withstand the natural swings, but no amount of bankroll means you'll be a winner.

If you want to take a shot at a higher game, why not? If it doesn't work out, you'll have a better idea of where to improve. If it does, you have the bankroll to play.