No its correct, having 2 kids and rate of sickness went through the roof, same for my wife.

We also had 10+ covids to indicate how much it changes, mostly imported by kids from creche (we hit the 'right' timing with them and covid waves). What do you expect when they shared pacifiers and put fingers in mouths all the time. Or suddenly sneezing gunk all over my face when holding them.

Before kids, I was usually sick 1x a year for few days, or had 1 proper flu week and that was it, my wife even less. No it didn't visibly improve our immunity, had covid last autumn and it felt almost like for the first time, sans loss of smell and taste.