I'm in my mid thirties, and did not get into programming until around your age. Didn't get a real programming job until 2-3 years ago. There is some ageism in tech, but I don't think it starts anywhere near your thirties; or even fourties. There is competition of course, but I am not seeing that when applying for non-FAANGS or when freelancing. Bring skills to the table, be able to work within a team, and market yourself and your skills; and then it doesn't matter if you're a programmer starting out at 15, or 65.