I'm worried about my weight i'm a bmi of 16.4 always been very skinny i'm 1,83 tall. should i push my weight to at least 17???

Low body weight: Some people are thin naturally and healthy. But you list a lot of conditions. You are quite tall. You should get checked for hormonal disorders as a root cause (GH excess, hyperthyroidism). Also, ask your doctor about Marfan's syndrome.

Underweight.: That BMI is underweight, and therefore unhealthy. This should be investigated, as there may be a medical reason for it to be so low.