I don't believe you are too old to make the change. Even with the relevant training (if necessary, you failed to mention your license) and type rating, and of course presuming you get an airline job quickly, you'll still be breaking into the airline world before you hit 40, so with at least 20 years to go as long as you stay healthy.
On the other hand, I think you should seriously consider your motives for this change. What you are saying about GA, and what you have heard about GA from other pilots in other companies are what you will hear from many airline pilots if you speak with them as well. Or just spend an hour or so each day reading posts on Pprune written by active airline pilots. Just because you stop flying corporate and take the step to a (probably) bigger bird doesn't mean you leave corporate behind. If anything, in my experience there is even more of that bull**** in the airlines.
Fixed schedule, standby days, not doing odd jobs or waiting for maintenance to deem that the bird is ready to fly sounds good on paper but many airline pilots will tell you that especially in your first years and even more depending on the airline you will see a lot of the things that you want to leave GA for. Don't forget: the grass always looks greener on the other side of the fence.
I'm just saying look at both sides of the story, and don't take the leap until you have.