Patk, one of the rules I live by is to NEVER compare myself to others. There is just no comparison between you and your brothers; or you and your acquaintances. Where you have unique strengths and talents, they do not. You may not be able to see them right now, but you will.
Another rule I live by is that whenever I feel guilty, I stomp it out. The past is past; live for today. Easier said than done, I know, but once you teach yourself to recognize guilt when it comes up, and once you recognize that it will POISON your mind and your life, you will be better able to make healthy decisions for yourself. And remember, you may have been immature, but THAT is exactly what your teenage years are for: to try things out and do the best you can; but it's really only practice. As you get older, you will see how far you have come since then. Try not to be so hard on yourself. We were ALL teens once and we all did stupid things back then.
One thing that helps me immensely that I have recently learned to do, is to cultivate a life of gratitude. Try to find the "blessings" in all that you see, think and do. Be grateful for the small things in life. Thank your Dad for helping you to get that job and you will see that something comes of doing so.
Lastly, it is NEVER too late to start changing your life. I can't tell you all the ways I messed up from age 13 onward. I spent my entire twenties drunk and doing stupid things. I honestly don't know how I made it. But I sobered up and when I was about 31, I went back to school. I worked for the school and received housing for payment, and I lived with three 18 years olds on campus. I didn't finish college until I was 35 years old but I did it. My life is a hundred thousand times better now.
Look toward the future sweetheart. Keep your head up and your eyes straight ahead. Don't look back, don't look down, don't look side-to-side; just straight ahead. You're doing great!