26, you're not too old !
But do it now, will be one of the oldest of your classmate. But if you go integrated in a big school, you have good chances to get a job straight in an airline.
Dr Mike oxygen, of course 43 is way too old. It's not impossible, some guys win the euromillion at 43, which is statistically harder than getting a flying job.
Your chances of being successful are very small, but, depending of your money/family etc, you can go for it...
And get a first time pass at the IR, good training reports, etc on your CV is peanuts compared with your date of birth.
Most of my young classmates have been called by ryanair for interview, all of them got hired. My results at the exams were better than some of them. I never been invited.