She is still relatively young.
She's only young relative to the dinosaurs running in the US Presidential election. She's 18 years older than Macron, and 9 years older than Panzergirl. Looking at heads of government around Europe, she's older than Johnson, Sánchez, Rutte, Orbán, Conte, Kurz, Duda, Mitsotakis among others.
She's only 5 years younger than Merkel who's been Chacellor of Germany since most posters on this site were still wearing diapers.
I really fail to see how she is so young that she can sit out 2022 and run in later presidential elections. If she wants to be president, 2022 seems like the ideal time to do it, or she'll be old news.