@athin has found the mathematical pattern in the sequence and created a useful general way to display it pictorially (go see their post and upvote). However, a slightly more accurate diagrammatic rendering would be as follows:
This is because the sequence reflects:
The significance of 23 March in the hints is that:
The pattern emerges as:
Why does the ...
Congratulations, I am assuming you have recently become a mother/father. These are the ages, in months, that doting parents use when someone asks "how old is he/she". If I remember correctly, the next one is 18, after which the series steps back to 2,3,4...(in years).