I have had maternal transference with a T who was only 2-3 years older than me. I have had Ts 5-10 years older than me for whom I had no significant transference.
My current T is 20 years my senior and the transference is much stronger than I’ve had before, but... so is the connection.
Transference is not a rational response, it is an emotional response. Age doesn’t matter, but experience and connection do.