There really isn't a normal weight for anyone regardless of age and gender. Everyone has a different body shape. So instead of thinking whether you are "normal" or not, consider thinking whether you are healthy or not.
And guess what? You are healthy! Your BMI is 18.6, which means you are in the 71st percentile for your gender and age. This means you aren't overweight (95th percentile or above), at risk to being overweight (85th percentile to 95th percentile), or underweight (5th percentile or below). So I wouldn't stress out. You're just fine the way you are.