You're probably okay as long as you know how ignorant you are and don't try to pretend to be an expert where you are, in fact, ignorant. Many, many people pretend to be smart while showing their ignorance, then whine when more knowledgeable and experienced people point out their ignorance. Don't be one of those.
Much of that is conflated with bigotry... (I, for instance, don't have a lick of respect for people who claim to know all that's needed to know about spiritual matters when they proudly proclaim they haven't done any research and act like casting even a sidelong glance at someone's scripture will melt their faces off). I don't have a lot of respect for men who claim to be experts on feminism and women's issues, either - maybe it's one thing if they've been involved with their wife/mother/sister or work in the medical profession, but if they're "white knighting" on behalf of my "kind" and show they don't know dip about me, that's another. Likewise, I don't think people have a clue about what mental illness is like unless they have one - and psychiatrists and therapists only come close.
And, for the love of ponies, if you're going to write stories involving characters riding horses everywhere, research the care and keeping of equines...
So, I'd say... "A bad thing if you pretend to be a know it all" about ignorance, but if it's an honest ignorance that you're willing to dispell via research, education, or *just talking to those scary, scary people who are different from you,* then, it's not such a bad thing. Children are ignorant of a lot, that's why good parents teach them and send them to school.
Then, there are some things that it's good to remain ignorant of all around. I want to forever remain ignorant of what it feels like to kill someone, for instance, or what it feels like to die by electrocution.