of course u dont. u can be a web designer from your home, u dont even need an office. degree is something to prove that u went on classes and passed some papers/exams. it does not prove u have the needed knowledge.
College is a lot easier when you're young because of grants/loans/etc. Once you got a full-time job, getting a degree will be hard. You may also find a pay cap or lack of advancement because of no degree also. Not really a chance you would want to take. Not to say it's not possible to land a great job w/o one