I'm slightly taller then you and am aiming for a healthy weight of 155. Depending on your bone structure, you can go from 138 to 158. Based on the body mass index, you are already below your ideal weight. I used to weigh 130 ~ 5' 8" and was always considered too skinny. Now that I'm 25 years older, I'd be happy with 155.

also noted that you have a four year old. The soft doughy skin that you talk about are probably from having a child, not from excess weight.