I created a linear regression model that involves age (X) and weight (y) in which I show a strong positive linear relationship and shows that as we...

I created a linear regression model that involves age (X) and weight (y) in which I show a strong positive linear relationship and shows that as we age we gain weight. I used the age range from 20, 30, 40, 50 and 60 year old random people as shown below. My question is, would I be able to apply this model to the weight of a new born? Is this problematic?