I don't have any data to back me up but, anecdotally, older PhD students tend to do well. I know many colleagues who finished their PhDs in their late thirties and even a couple of them who finished their degrees in their forties (one of them teaches at West Chester U.) I say go for the PhD.

Pedro.

Yes, go for it. When I was a graduate student in the early 1980s, English professors told me not to go into English because there were no jobs. Yes, they actually counseled me to drop out of the program. When I finished my Ph.D. in 1985, I had so many interview offers I could not respond to them all and have always had work since then. If you do what you know you need to do, it will work out.

dwl