My dd is 6 and has waist length Botticelli curls. Until she was 4 I really struggled with keeping it nice and then discovered a book called "Curly Girl". I use to shampoo and condition, and her hair was a nightmare. Now I give its good scrub in the bath water and then use only conditioner which I only halfway rinse out. A bit of leave in conditioner and the brush glides through. Her hair is bouncy and gleaming, not at all greasy as I thought this method would make it. Strange to think her hair hasn't been shampooed in 2 years but it's true.
I do occasionally straighten it with a flat iron at her request but would never do it chemically. Gorgeous curls are worth the effort IMO.