How to maintain or gain weight in a healthy manner?

Hi everyone. I am around 95 lbs, 5ft and 17 years old. I’ve always had a pretty fast metabolism so it’s not always the easiest to gain weight. I know the doctor has said that I am at a healthy weight for my height and age but I’ve always been a little self conscious about being sooo petite. Ideally, I’d like to get to at least 100 lbs but so far that has not been working. Do you think I should or shouldn’t and why or why not? Do you think it may be better to maintain my weight as is? I would appreciate any tips and opinions to either gain weight or maintain it in a healthy manner.