I started at 35 only because sport climbing hadn't been invented until then.
"Be responsible for your actions and sensitive to the concerns of other visitors and land managers. ... Your reward is the opportunity to climb in one of the most beautiful areas in this part of the country." John H. Bronaugh
I started at 27 and within 6 months (climbing twice a week in the climbing gym) I could top rope send 5.10C's and onsight lead 5.9's at the gorge. I read that it can take up to a year of climbing to develop maximum finger strength, but you will notice a big difference after just a few weeks of climbing. The only complaint I have is that most of the routes at the gorge are 5.10 and over, but I see it as only a matter of time before I start leading 5.10's anyhow. If you go with a group of experienced people you can top rope some 5.10 and over routes anyhow, that's what I always do. The last time I went(at month 7) I almost top rope sent a 5.11C slab at the Playground. I flew past the crux, but I should have shook off more on the giant jug near the finish and I would of had it.