My daughter is about to turn 12 and my multi-year plan to turn her into a gamer completed awhile ago and she’ll play anything now.
She started off with Enchanted Forest and Sleeping Queens and a nurtured love of competition.
We skipped over Monopoly and those type of games so she wouldn’t get stuck there and instead jumped to some easy to play real games like Patchwork and Splendor and For Sale and that card game where you take the card or place a chip. Then she got into Smash Up and we did a little Dominion. Then Sushi Go and Castle Dice for some drafting action that also has engine building and resource management. We also played Castle Panic for a co-op.
Then she moved on to actual real games like Power Grid and Yokohama and Dominant Species and Scythe pretty quickly.
I think the key was introducing the key gaming concepts with simpler games that focus on the one concept, making it easier to grasp how they intertwine in more complex games.
Splendor for engine building is great to introduce to non-gamers and is a pretty pure engine builder.
Sushi Go for the drafting also appeals to non-gamers.
Dominion for Deck Building
For Sale or Modern Art for auction
Ticket to Ride for contract fulfillment and route building.
Settlers of Catan for resource management and hopefully instilling in them a desire to control your destiny more than just dice rolls.
Then get them into a worker placement/action selection game or two, since those are the core mechanics of so many games. Which ones to start with would depend on what other mechanics they tend to like plus theming etc.
I think Istanbul is a good one for early on as you select actions, but have some limitations, and are doing resource gathering and engine building and have multiple paths so can focus on the strategy they are drawn to and even a game where you win by a lot of turns still looks close since it’s “5 gems to 3” rather than a score of 200-85 like some games.
And once they get Istanbul and like it, they can go straight to Yokohama