Besides the pics that LD has, I haven't really seen/noticed Jada's real hair in years. Last I saw/noticed her natural hair was long ago, and it was quite short. "Long" for me is past shoulder length, and her hair was definitely past shoulder length on this recent show I saw her on. It really looked like her own hair to me. I think its entirely possible that she could have grown her hair and if so I would LOVE to find out what she did.
Even assuming her hair was short in 2000, it is entirely possible for her to have past-shoulder length hair by now simply based on my own experience -- I was nearly bald after a stylist put SUPER wave nuveau (spelling?) in my hair. I was so bald that I didn't have enough hair to "weave" for a month afterwards & I had to wear a wig. About 1.5-2 years later my hair was past shoulder length due strictly to wearing a hair weave. So yes I believe it could be Jada's real hair that she grew herself.