age regression isn't an aesthetic. it's a ptsd symptom for some and a coping mechanism for others. some aesthetics that you might mean when you say "agere aesthetic" are kidcore, babycore, toddlercore, toycore, and nostalgiacore. there's a lot of misinformation about this

the difference:
age regression - your mind reverting back to a younger state due to trauma or a need to make up for a lost childhood. can be a symptom or coping mechanism.
kidcore - a set of aesthetics revolving around childhood, usually for fun

some better terms for aesthetics like this would be nostalgiacore, babycore, toddlercore, and cutecore!

sanriocore is a specific term for aesthetics like this revolving around sanrio characters! it's a subset of kidcore/nostalgiacore

images like this can be called toycore or rainbowcore, or just plain kidcore. kidcore is an umbrella term that can be a general aesthetic or any one of its subcategories

if you're looking to tag nostalgic websites you looked at as a child or "kiddy" websites, you're probably looking for the terms webcore, 2000score, and nostalgiacore

hopefully this thread helped someone, or at least taught you some new terms!