First of all, the only thing they can do to force you to pay is sue you. If they don't sue you, then they can't force you to do anything. All they have right now is just a written agreement you signed promising to pay. That by itself doesn't have legal power to take money from you. The worst they can do without suing you is put negative information on your credit report (which has probably already happened anyway).
If they sue you within the "statute of limitations", they will almost certainly win and get a judgment against you, because you did agree to pay. With that judgment, the court can force you to reveal your income and asset information, and they can take the judgment to do things like seize money from your bank accounts and/or garnish your wages. And the judgment does not go away.
However, if you have no money in the bank and/or income, they can't take any money from you, because you have none. They can't take more from you than you have. In other words, if you have no money or income, and won't have money or income soon, the judgment they can get by suing you and winning isn't worth the paper it's on. Since serving you and suing you takes money and effort, they will make a calculation on whether it is worth suing you based on the amount of debt and what amount of money they think they can get from you based on what they know about you. This is the reason why you may not be sued at all (if they calculate that it is not worth it), and also why they may offer you a settlement for a lesser amount (because is saves the cost of suing and the risk that they won't be able to get you to pay). The amount you mentioned (several thousand dollars) may be small enough for it to be not worth it.
Another thing is the statute of limitations I mentioned earlier, which varies by state and is several years long. If they sue you after the statute of limitations passes, then you can raise the statute of limitations and get the lawsuit dismissed. So basically, after this amount of time passes, you are pretty much free from this debt. Note that the statute of limitations "resets" if you acknowledge the debt, which includes paying any amount on the debt or agreeing that you owe them this debt. So if the collection agency ever offers you benefits if you just sign a promissory note, or just pay a token amount, don't fall for the trap -- they are trying to reset the statute of limitations. Even though it's true that you owe them the debt, never let them hear you acknowledging it, unless it's part of a final settlement.
Finally, if they get a judgment against you and you don't want them to have the ability to take your money indefinitely in the future until the debt is satisfied, there may be the option of bankruptcy. However, a few thousand dollars may not be worth the cost and negative consequences of bankruptcy, since as a young man you should be able to earn that amount quickly whenever you start working.