bling_bling; You are 20. I don't consider you a kid. Just not financially self sufficient maybe. Possibly lacking of a bit maturity. But, technically you are an adult. Adults have to learn to face the music when they do something wrong.
In this case, you and your gf need to talk things through between yourselves first and decide what is the best course of action. Know what you can do and what are the consequences. But I can tell you the first course of action.
1) Go get a pregnancy test kit. If negative read 2). If positive read 3).
2) Relax you might have escaped the bullet. Don't do the same mistake again. But to be sure, try the test a week or 2 later again, just to be sure. If positive then read 3).
3) Congratulations. Now you have to go bring your partner to a Obs/Gyn for consultation. This is to confirm. Now;
i) If the both of you decide to have an abortion, you can tell the doctor your situation and he'll mostly help you. Remember what you are doing here. You are hurting your partner's body and you are taking an innocent life. Remember this.
ii) Return and consult your parents, the both of you. Despite you fears of getting a smackdown from them, they are you parents and they should at the very least be informed. They may or may not help you. But if you feel helpless by yourselves, it may be better to get help or guidance.
iii) You can talk to help groups. There are many. They would probably be more equipped to give you good advice.
The general things you got to think about are the well being of your partner, because for all your fears and anxiety, imagine how it is for her. She's got to go through more than you do regardless of what decisions you guys make. You owe her big time. Also think about the well being or future of your child (if indeed she is pregnant). Could you possibly give your baby and good upbringing? Money is just a part of it. Could you be a good father? Could she be a good mother? Could you both be able to live with each other and the baby?
At the end of the day, life is about making decisions. Most of them tough. Now you've got to do what's best for all parties, not just yourself. You've already made a wrong move, so now's your chance to make a right one.