Underage characters (that is, characters under the age of twenty) have it a bit harder here.
If you are 18 or 19, that is, out of high school already, you can enroll in college by taking a college examination. How you pay for college...well. You will get SOME government money, but you will also need to get a job. Part-time jobs do not require contracts, but they do not pay enough for you to afford a higher-priced private institution. If you are in college, you can at least live in the dorms...but trying to pay off those dorms will probably be suicide on your life.
If you are high school age, that is, 15-18, it is possible to live on your own with a guardian's signature. The best bet for people who are between these ages is to pair up with someone over twenty and have them declared as their legal guardian so they can attend high school and find a place to live. It is not compulsory for you to attend high school, but it will lead to a better life for you, plus socialization.
If you are under the age of 15, you have it the worst. You HAVE to live with someone, or you will be placed in an orphanage. Some of them are nice...some of them aren't. They all have internet that you can use.
Lucky children will be placed in foster homes. Again. Some are nice...some just want the money that goes along with it. If you decide to be placed in one, it's up to you which one you get.
Note: It is very possible to lie to your case leader at City Hall about your age, and receive an ID that says you are older than you are. However, if you go too high, you will receive whatever age is at the discretion of your case leader.