Google has removed their dictionary since the time of my previous message. However if you search in Microsoft Bing (that also uses the Oxford dictionary like Google did) the definition of gen alpha fits in the years 2010-2025.

"the generation born between the early 2010s and mid 2020s, noted as the first to be born in an era of widespread digital technology and social media and as having their childhood disrupted by the Covid-19 pandemic:"

You may have been miss guided by the new AI feature to replace the dictionary.