I can understand that feeling. Certain types of people make me feel like "a kid" (I'm 34) or extremely inferior. I feel guilt and a whole lot of self hate for not having a job and I tend to get really snotty (mostly in my head) and pissed at random people because somehow they are able to work and I am too freaking weird...I always feel more comfortable around kids, well, not teenagers...but younger kids are great. Maybe its because I have a 9 year old?

Anyhow, I have no clue what qualifies as PTSD or not, so I cannot answer that, but you aren't alone with the feeling. I tend to think of it more as feeling inferior, rather than as a kid, but I think its similar to what you are describing.