19 is a tough age for a guy. Females tend to be interested in guys either their age or within a few years older, and a guy who is just a few years older than you is more likely to have his own place and a car. Meanwhile, the girls who are likely to admire you because of your age are possibly too young for you, from a legal standpoint. So you need to seriously compete for the women your own age, and that probably means behaving in an assertive and confident manner.
Good decisions come from experience. Experience comes from bad decisions.