All the sources I can find state that jury summons are sent at random, so some amount of variability is normal. E.g., your neighbor gets summoned 4 times in 10 years while you don't get summoned at all.

The prospective juror pool is drawn from voter registration and driving licenses. I've had a license since 16 and have been registered to vote since 18. I got a summons, actually two at the same time (one federal court, one state court), soon after turning 18. I needed an exemption from both as I was attending university full time 300+ miles away. Then nothing, across 3 different states I lived in & registered in, until I was over 40. I guess I'm on the left side of the probability distribution curve.