This is not strictly a reply about freelance writing, but at your age I was struggling with the same dilemma, the desire to write vs the need to have income to live on. What I know now, I know from having made lots of mistakes and only in the last few years (and some major life implosion in the process) have I actually come back to writing.
Also, most of this applies to fiction writing, which I gather is your interest from your post history.
If you love writing for the sake of the art, trying to channel that energy into making "enough money to live on" from writing can threaten your enjoyment of the writing (and if, like me, you have anxious tendencies that cause you to freeze under pressure, your ability to get anything written).
Freelancing for a living limits your ability to be choosy about projects. There are fairly limited opportunities for fiction writing; most postings are for nonfiction. A lot of it these days comes from "content mills", websites that will pay you a little for lots of copy that they hope will generate them lots of Google hits and advertising views. If you go the freelancing route, you have to be highly organized, self-disciplined and self-motivated, you have to go looking every day for job postings, you have to know that you're not going to get every one. (My friend who's spent his life contracting in software development repeatedly tells me it usually goes (roughly) 100 postings, 10 nibbles, one offer.) It's not all necessarily dismal...if your goal is to become a respected freelancer writing for big name publications, you can certainly get there this way. If your goal is to be a published fiction author, by the time you get through the days work of earning a living, you're not likely to have any energy left for your own work.
The stats for fiction writers are pretty dismal - most published writers, even bestselling writers, will struggle to make a livable income from their work. If you value and want to preserve your vocation of writing as an art, it is best to let go of this expectation. If you manage it sometime in the future you may consider yourself very well off. If you make it a precondition of writing--the biggest mistake I made--it's not going to work.
These are the things I'm either doing or working toward doing now:
Keep writing, no mater what. Write every day, or as close to it as you can, even if it's only a few hundred words. Write for yourself. Write what makes you happy. Even if it never sees the light of day, no writing done with this goal in mind is wasted. "The first million words are for practice" is a saying I see a lot. (Whereas, to paraphrase Neil Gaiman, if you write something only for the money and the money falls through, as it sometimes does, you're out both the money and the enjoyment.)
Get a good "safety net" job. If it's something in a writing-related field that gives you experience and doesn't drain you creatively, great. If it's not writing related, it should be something you like enough that you can do it long term and won't burn you out from the stress and dissatisfaction, something that feeds into your other strengths and interests. Make sure it leaves you enough time/energy for writing to happen.
Do keep an eye on the freelance gigs, but with a safety net you can afford to be more selective. Apply to those that interest you. If you get any, follow through; you want to establish yourself as a reliable person to work with. For fiction, a lot of work these days comes from game developers so it may be worth reading up/practicing with some of the particular quirks of writing for interactive media. (Gamasutra.com is a wealth of both information and job postings here.) You may also need to put effort into building a portfolio of sample work.
If you have other interests that can be turned into "side gig" work, these are possibly worth perusing too. It will take more time, but if you can establish something that brings you income independent of "working for a living", you won't be as dependent on your safety net job.
When you feel you are ready, feel free to start working on stories you want to submit for publication to various outlets. (Stephen King's book On Writing has some nice overviews of how that tends to go.) Expect rejections. Learn to deal with them, learn from them, strive to constantly improve the quality of your work. There is no set expectation for how long it might take to "break in".
Live life. There is a world outside your word processor and all of it is potential creative fodder, even (especially) the bad parts. I regret that I pretty much stopped writing for several years thinking it was more important to do something I could pay the bills with, but I could not, at your age, have written the kind of work I've written now that I've had a decade+ of life experience to draw on.