Daughter’s friend

My 9 year old daughter has suddenly become best friends with a girl in her class that she only knew peripherally until this year. They want to spend all their time together but I have some reservations about that. From what I’ve gathered, this girl can be quite disruptive in class, and isn’t a good influence on my daughter, though I know my daughter is a good student and will be fine at school. What’s bothering me the most is that lots of other people seem to think this girl and her family aren’t so great. Other moms have told me that they didn’t want this girl in their Girl Scout troop because of her behavior and because of her mom being bitchy and entitled. Our neighbors know this family from swim team and don’t seem to approve of them. The mom herself has told me how multiple teachers have singled her daughter out and treated her unfairly, which I sympathize with, because this is a child we are talking about, but I also can’t help but think that these teachers whom I very much respect might be on to something. I realize I’m letting other people’s judgments influence my own thoughts on this family, but I’m wondering if so many people that I like and respect say that this family is basically no good, am I just being naive in letting our families spend time together? The Mom and I have had some good conversations but I also find myself judging her because she smokes and can be kind of confrontational (not to me but to others). I feel myself looking down on her in some ways. I can’t figure out how to navigate this!