The Witcher

In an interview with one of the showrunners, Lauren Schmidt Hissrich, she says:

Is this crazy? Like, is it crazy to do that with this story? Is it crazy to say that Ciri's (Freya Allan) story takes place over two weeks, Yennefer's takes place over, you know, it's like 70 years. Geralt's (Henry Cavill) takes place over 20 years. Is that crazy?

If she was, say 20, when she went to Aretuza, she would be 90 towards the end of the show. Perhaps not 3 lifetimes, but certainly 2.

As I watched, the details I caught that led to realizing the [timelines] were:

• During the mage's council discussing where to send the new mages, they refer to Calanthe (Ciri's grandmother) as a young, promising princess [Yennefer]
• [Geralt] is fighting the shtriga for King Foltest, but we cut to [Yennefer] who walks past a child Foltest who is pestering his sister.
• [Geralt] attends Ciri's mother's betrothal/wedding where we find out she is pregnant.
• Once [Geralt] and [Yennefer] meet, when next we see them together during the dragon hunt there are flashbacks of several meetings that occurred in the meantime.
• Finally, [Yennefer] is talked into helping the mages defend Cintra, before anything in [Ciri's] time.

Those are just the ones that I caught and I wasn't trying to pay too much attention once I realized the timeline differences. This Screen Rant page includes many other smaller details that I missed. It also includes this timeline from dates in the novels:

1170 - The Great Cleansing of Elves
1173 - Yennefer is born
1190 - Yennefer attends Aretuza
1230 - Yennefer becomes mage of Aedirn (approx.)
1232 - Calanthe named queen
1233 - Calanthe wins The Battle of Hochebuz
1234 - Geralt meets Renfri
1235 - The Usurper overthrows Nilfgaard
1237 - Princess Pavetta is born
1252 - Princess Pavetta is married
1253 - Ciri is born
1257 - The Usurper is killed
1260 - Yennefer and Geralt meet (approx.)
1263 - Nilfgaard invades Cintra