If you know how to write well and writing is your passion, then you can become a copywriter without actually having a degree. But getting a formal education and holding a degree will most likely land you to a higher paying job. Oh, you could say that you have years and years of experience writing but in our present world where everything is computerized, most companies don't just hire people based on what they can do but it's usually based on what they have. Come to think of it, why would they hire older people without a degree when they can hire young copywriters with degrees to boot and don't demand a high salary? You could be a great writer but that does not guarantee you get the job.
To be able to compete with the young ones, you need to have a degree. You don't have to worry though because you don't need to go back to a real school to get a degree. You can study in your own time and work at the same time. After you finish your short course, you can already start applying for a higher paying copywriting job. Or you can even start your own freelance copywriter business. AWAI or American Writers & Artists Inc. can make both things happen to you. You can get paid to write or build your own business.
With your talent, skills and don't forget the degree, who says you can't compete with the young ones?