Contracts - know what you are signing. Now that you are 18, Pennsylvania courts will hold you responsible for your promise to pay if you enter into a contract. Whether you buy a car or rent an apartment, READ and UNDERSTAND the contract. If you don't understand something, ask an attorney, parent, etc. When you enter into a contract, it is an agreement that creates legally enforceable obligations.
Being held legally responsible for something means you can be sued. Since you are an adult, securing legal help also rests on your shoulders. While your parents may be there to offer either financial or emotional help, you will be the client who needs to hire an attorney.
Don't let anyone rush you into signing an agreement before you understand what it says and do not sign a contract until all blanks are filled in.
Make sure that you READ and UNDERSTAND the contract before you sign anything.
If you don't understand something, ask an attorney, parent, etc.