Brain-Teaser 511

From The Sunday Times, 28th March 1971 [link]

I recently had an odd letter from a puzzle addict, who wrote:

“I know that you are between 25 and 80, and I’ve made a bet (at fair odds) that I can deduce your age from your Yes/No answers to the following questions:

1. Are you under 55?
2. Is your age a prime number?
3. If the digits of your age are reversed, is the result prime?
4. Is the digital root of your age even?

Please reply on enclosed stamped postcard.”

I did so, and had a reply a few days later:

“Many thanks. As soon as I read your first three answers I knew that the fourth answer must lead me to your age. You are …” (and he gave a figure wrong by well over 20 years).

Puzzled, I rechecked my four answers and found to my horror that I had carelessly transposed two of them and so had misled him.

How old am I?