Is it normal for my penis size to increase?

Most of the human penile growth occurs between infancy and five years of age. There is additional growth five years after the onset of puberty. 

Studies have been both positive and negative regarding correlating the size of the penis and other body parts. Some genetic (for example, endocrine and/or hormonal disruptions) and environmental factors can affect penile growth. Age does not seem to have a negative correlation with penile growth.