It's definitely possible ... it could turn curly too. Mine was straight until I was 13!
Hair Type: Combo of 2A, 2B and 2C ... with a weird straight underlayer
Fine, normal porosity, normal elasticity.

Currently using:
Low Poo: Yes To Cucumbers Color Protection Shampoo
Cowash: VO5 Moisture Milks
Styler: KCCC
Gel: Herbal Essences Totally Twisted Gel, Tigi Bed Head Creative Genius gel

Started CG 9/10/13