Your weight and height correspond to a Body Mass Index
of around 38. This means that you are grossly obese
as the normal BMI lies between 18 to 25. You have a very high risk of heart disease
nad many other diseases. However, you need not be embarrassed about it because with determination and will power you can lose weight and get into the healthy BMI. Try to exercise everyday for an hour, restrict your food intake, watch the calories in the food you take and join a gym if you need motivation.
About your other question, there is absolutely no relation between losing weight and penis size. Since you are already 17 years old, its is highly probable that you have already attained adult penis size and it is unlikely to grow bigger or smaller in size henceforth, except during erection.
Hope you lose weight soon