I was a career changer, completed a modular CPL/IR aged 36, first airline job a few months later, now longhaul BA.
It can be done (and UK employers are not allowed to discriminate on age grounds), but be aware of what you are letting yourself in for.
(a) Timing is everything. Qualify at the peak of the job market (like I was lucky enough to do) and you might wonder what all the fuss was about finding your first job. Qualify at the start of a downturn and you might take years trying to get a job - and spend thousands on IR renewals.
(b) From experience, learning new stuff becomes more of a challenge as you get older (old dogs and new tricks...). Not so much of an issue in my thirties, but now I'm closer to 50 it's noticeably harder to get my head in the books and absorb new material. Or maybe I'm just not the sharpest.
(c) Training will cost a small fortune (modular) or a large one (integrated) with possibly a type rating to pay for as well. The longer you wait, the lower your career earnings potential. Paying off a £100k training debt will take a long time, and it would be nice to enjoy some financial rewards before you start worrying about retirement or whether you'll get through your next medical. It was several years before I was earning the same as in my previous career, and closer to 10 years before I could really start saving money.
Don't think I'm trying to put you off - I don't regret the career change for a second, and it still beats the hell out of working in an office. Just make sure you've done your homework before committing.
Feel free to pm me if you want any more advice.