I have the same type & length of hair, and I totally agree with Aquilah's advice. I would advise the following:
1.
Don't use heat on your hair more than once a week.
If at all possible not at all. I went over a year without flat ironing my hair. I know how to wrap my hair so it comes out quite straight.
2.
Find good products and stick with them.
I found good products that work for my hair and I have stuck to them. I've been using the same for almost 2 years. I use almost everything Organic Root Stimulator perm, oil sheen, wrap lotion, moisturizer, and conditioner. The other wrap lotion I use is Lottabody's Wrap'n & Tap'n.(I dilute it first.) CuTeLiCiOuS metioned C of Nature shampoo. This is also the only shampoo I used outside of when I get a perm. I can
totally comb out my hair and only have a few hairs in the comb before I start wrapping.
3:
Don't blow dry, wrap & sit under a dryer.
I always wrap my hair after a shampoo. I only wear my hair straight so this works perfectly 4 me. I don't even have to use a flat iron to get get the straight look you have in you pic.
4:
Tie your hair up @ night It's critical to wrap & tie your hair up @night (with a satin/silk scarf), or at least wrap your hair up and sleep on satin pillowcase.
5. Use a cholesterol conditioner every 2 weeks.
I like Silk Elements Mega Cholesterol Cond't @ Sally's.
Your hair looks great. If it's all yours you may not need this advice. If it ain't broke don't fix it.