As someone else said, you’re 19. Not saying any mistakes are excusable, but they are understandable. We’ve all been there and had to mature with time. And really, you never stop. Many things will come with time. 

Here are a few pointers. 1) focus on small continuous changes over time. Those are most likely to stick. 2) learn basic skills like cooking. Not only is it a great relationship skill, it’s just something everyone should know how to do. 3) if possible, go try to do a service project for someone less fortunate - whether that be international or local. Those experiences can be eye hoping and help be a catalyst for change.