I am very immature for a 30 year old. Even though intelligence make me interested in the medical stuff,(which is why I am going to school to study histology, the study of tissues in the body.)
Everything else, I am very immature, but i do not think of it that way. To everyone else I may be, but to me there is no such thing as age appropriate activities when it comes to someone's interests,mannerisms, or feelings.The only thing I see that should be considered and counted for age appropriate is anything that is dangerous,sexual related, or 'adult related provocative activities" where I believe under 18 is too young for that stuff.
The activities that I am interested in(which are considered by society as immature and inappropriate)is with playing with toys(educational math toys, and even baby toys) and playing with play kitchens where I feed my stuffed animals. To me my stuffed animals are the only family I have because I am not capable of having relationships because of my Asperger's, so my stuffed animals are my family(and they need to eat too.) I love advanced math books and crossword puzzles and computers and other college level and adult level academic activities, I do these things like I am playing school. I have a school desk and everything. I have my room decorated with Winnie-the-pooh things even though I only like the Winnie the pooh because it makes my room like a toddlers room.
Since I am child-like in nature and I am emotionally a 3 year old, sex and relationships are out of the question because I have too much of a child-like innocence that those things bother me too much and when I am asked by doctors about that subject, I tell them it feels too perverted for me and that I am too young,even though I am 30 and will always be "too young".
The way I carry myself is very child-like. So basically I am a 3-4 year old with the intelligence of a genius 100 year old, with a body of a 14 year old, who happens to be really 30.