I’m 26 but I feel like I’m stuck with a 15yr olds mind

So to give you some background on me I grew up sheltered with strict Christian parents, have you ever seen the horror movie Carrie? My mom was was very similar to her mother when I got my period I didn’t even know it was a period until she came running home with pads and telling me small details about it. I remember being 21 and still asking for permission to go out with friends because I forgot how old I was, now that I’m older I still feel like when I speak to people I can’t grasp what they’re saying to me like I can’t have an intellectual conversation because I’m limited in knowledge, being in relationships with men make me uncomfortable because I have low self esteem and I’m very self conscious of my body I didn’t grow into a womanly figure like I saw around me and on television. I’ve been told my mindset and conversation is childish I want to be better I just don’t know how or where to start Is there anything I can do to help with these issues?