Thoughts on body waves?

I was thinking about getting a body wave put in my hair . It’s very thick (Ponytail circumference is almost 6 inches ) and about 3-4 inches past my shoulders. I haven’t dyed it or bleached it in a long time and I haven’t been using my flat/curling irons at all.

I think it’s pretty healthy. Anyway, my hair is pin straight and doesn’t hold a curl/wave for very long regardless of how long it sets or what product I put on it. I have never had a perm or anything other than color put into my hair.

I am also getting my hair cut a few inches and perhaps getting it thinned out but should I thin it out if I’m getting the body wave?

Like I said, I’ve never had a perm so I have no idea of how I should go about it. But everyone I’ve talked to has told me to take a picture of two of how I would like it to look and I love the last style on this page; http://www.mylilventure.com/hairstyles/three-great-ways-to-style-long-hair/