I know that the CS field tends to skew young, especially for entry-level work. Am I likely to face significant barriers due to my age?
Just do it.
Did you perhaps mean go to places where the manager is a good learner?
By the way, as an intern he was still learning. I remember one day he was running the longest, worst, non-infinite loop I have ever seen. It ran for hours! He asked me what was wrong. That was his trick. He would ask good questions and he would remember what he learned and applied it later. That's why he's such a great engineer. He still learns to this day. So, do it! And keep on learning.
You will experience ageism, so plan on cutting your own path in either consulting, freelance development, or founding your own company. Build your network - that is where you will expand your opportunities.
Don't let anyone ever tell you that you can't have a productive software development career at any age.
Yes I'm sure there is age discrimination in the industry and you might have he misfortune of encountering it. But based on your other comment, you seem to have a determined attitude which is great. Now quit inventing problems for yourself that don't exist and go spend your time doing something more worthwhile.
I suggest stuff like Cryptography, Machine Learning, blockchain technologies, networking, low level hardware programming stuff. That is what i think guys in 30's should be good for, the hard things all the kids run away from.
Things like web development are nowadays too crowded with young talent that, even if you get employed. you will feel weird. around teens and young adults.
As far as I have seen, as long as the HR thinks you have been on somebody elses payroll because of your programming for some time, they will gladly hire you.
Or you might go the 'Double your consulting rates' way, often proselytized by patio11 in HN comments :)