of adolescence and nail polish

Another sigh. My girl is all grown up. Today she spent the gift card received on her birthday on books (as usual) and nail polish. Nail polish? Yup, nail polish. We had a bit of disagreement on the color. The sweetie wanted black and I was horrified! (No way!) She demanded one good reason why she can't use a black nail polish. And I blurted "because it's so like cult!".

My, my...I wonder why I am so set against her choosing that color. I'm not really that negative when others apply black nail polish, but I just can't take it when it comes to my own 'little girl'. In the end, she compromised by choosing blue...after much mutterings and complainings.

I wonder if I am just old fashion. Or whether it is normal for a mom to be against certain things like a black nail polish. After all she's only an adolescent who needs guidance...Gosh, much that I want to be a liberal mom who lets her kids think and decide on their own, I know that there are just certain boundaries that I won't let them cross. Despite believing this though, I still get confused by a lot of parenting-related stuffs. Whoever did say parenting is a piece of cake?