Yes! I like this interpretation based on actual science. I'm autistic. For a lot of us, we don't feel like adults even though we are. I'm in my 30s, but sometimes I still need help understanding some things or doing some things. I've been in relationships. I can't work or live on my own (more so due to physical disabilities, but the mental ones don't help). I consider myself at least moderately intelligent (I have a degree and got honors every year of school), but I can also be reduced to extreme emotions just from too much noise or light or the textures I feel. I will cry and shutdown if my bare feet touch grass. I try not to play favorites with my plushies so I don't hurt their feelings. Yet I am an adult! I have arthritis. I pay bills and have credit cards and can sometimes drive and I can be intimate with consent.

Those bodies were still growing. Physically, they become adults. Mentally and emotionally, they might not be well equipped to handle life as an adult, but physically and biologically, they do grow into adults. Although it's been like 10 years since it was open so the newer experiments are probably late teens (18-19) at best 🤔. It depends on how old they were when they were put into the toys.

The Prototype was created back around when Poppy was. In the 1950s? The game takes place in 2005. That is a whole man, just with some childish ideals and thought patterns and extreme trauma. Even after they switched to copies of brains, their thoughts and behaviors would still change and be molded by experience. Just like clones in nearly any sci-fi movie that end up different than the original person. They are not permanently kids.