I had them same issues with my parents. I've always had wild hair though. I was the black sheep on the family. I had every colour dye, 2 sets of mohawks, and 2 sets of locks. My first set was all waxed up, and I ended up loosing all my hair after 2 months. Then I decided to go the natural way. They look god awful for about a year. every day my mom had to remark that they looked bad and messy and that they were just a phase and that I'd cut them when I needed to get a job. 5 years later, and she does't talk about it too much, but it still comes up now and then. She thinks I am too old to have locks andpiercingsand tattoos. It's a never ending cycle. Whatever I do, she thinks it's immature. You get used to it, and just keep telling them that they are yours, not theirs
As for my dad, he's just a racist pig, and thinks dreadlocks are for black people, and that I am trying to look black. That, you've just got to ignore. I nod my head and talk about something else. It's not worth fighting with him about. I know he still loves me. He just can't keep his mouth shut.
As for congo's, you should separate them at some point. There will be a time when they are too mature to do by hand and you'll need a razor blade. Figure out how thick you want them to be and try to keep them that way. Some people like thin, pencil width, locks. I love the huge phatty ones. My thickest is almost 2 inches wide at the root, and my thinnest is about a sharpie's width.
Remember, and remind people that your hair is yours. If they don't like it, tough. They don't have to have locks.
It's probably a good idea, though, to direct her to this site so she can hear from all of us that locks are clean, probably cleaner than normal strait hair