Is a bashful nature pokemon any good or should I keep breeding?

Bashful is one of the neutral natures, it raises and lowers the same stat so nothing actually changes. For playing through the story it's completely fine, you won't notice. For competitive it's a waste of a slot because a proper nature gives you a free 10% in one stat. Don't bother breeding again though if you're on a game with mints, a mint changes the stat effect and saves you hours of eggs.