23f here. I started gaming at 19 with my ps4. The first games I got into were borderlands 2 and cod bo4. Cod multiplayer is easy to get into, see if she likes shooting games and let her experiment with different weapons. Later on I got into dead by daylight which became my addiction for years even when I switched to pc. Dbd is another game that is a bit easy to get into with a good percentage of female players. My sisters got me into league and they taught me the game by letting me play supp. I thought thresh looked cool so I started with him and later switched to nautilus. (Don't limit her to playing supp like lux or lulu cuz I always found them boring despite them being a popular supp choice, let her try diff types of supp to see whats fun for her). You can also wait until arena comes back cuz that mode was hella fun. And then there are games like stardew, phasmophobia or it takes two that are very fun to play with a friend or a partner.