I would like to know at what age does the penis stop growing naturally? Is there any way to increase the size of the penis? Is there a way to fix minor curvature? My penis tends to go to the left when erect and stuff. Is there anyway to fix that?

Everyone is different. Growth usually continues into your late teens or early 20s, though most growth takes place during pre-teen and early teen years. There is no completely safe, foolproof way to increase the size of the penis. Many penises curve right, left, up, or down, sometimes slightly, sometimes significantly. It does not need to be fixed. You just need to learn to work with it.

If you are concerned about size, keep in mind that it's said that 3 inches is enough and average is about 5.