Daniel Ainsleigh's reply:
The short answer is “No”.
The long answer is “No”.
You haven’t left it too late at all. In fact, because drama schools prefer applicants to have some life experience, many people are in their mid-twenties when they join the profession.
That said, there are a few things you should be aware of. In acting you will always be competing with your own age group -people who could be cast in the same roles.
Many people your age will have a few years experience already and you’ll find them quite tough competition.
However, many directors are less interested in experience than they are in talent and usually the part will go to the person who is best for it.
Here’s my main advice: Train.
Entering the profession with no experience will be tough but a good training under your belt and you’ll be taken far more seriously. I’d always advise choosing a course that is accredited by DramaUK (the new face of the National Council of Drama Training).
Otherwise, if that’s not possible, find a good acting coach (I’m one but there are others too. check out the Acting Coaches Directory). If you’re interested in musical theatre, find a good vocal coach too.
So, no, it’s really not too late. It won’t be easy but if it’s in your blood that will just excite you even more.
Good luck. Live it and breathe it. You could make it happen.