Age is a strange thing to ponder for me, really. I recall something once said by an author of note (I'm pretty sure it was C. S. Lewis) about how part of him was 40 when he was 8 and part of him remained 8 when he was 40. I'm 22 at present, and I feel very old indeed, but I also feel disturbingly infantile sometimes. Part of me feels guilty over feeling old, due to how ridiculous that must sound to anyone who's 40, 50 or 60, and
not 22, but I honestly think personal growth, life experience and outlook make subjective feelings of "age" very flexible, regardless of how advanced in years we are.
On the one hand, I'm used to feeling older than I am. I was a very fast developer as a child, and I was always "ahead" of my years, in various ways. In primary school, I was basically the classroom assistant. The other children would raise their hands and ask the teacher if
I could come over and help them. It stopped me getting bored, made me feel useful and apparently it was a help to the teachers. I always developed quickly, and was always extremely "responsible" for my age. I'm told how I sometimes got impatient with adults for their foolishness, how I basically acted like a little adult myself much of the time. In adolescence that was even more the case - I was explicitly told at age 14 by my closest teacher that "it's like having another adult in the room". At around the same age, I was sometimes told without exaggeration and in full honesty that I'd do a better job organizing the school departments than some of the teachers who actually held those responsibilities. By 17, my nickname among family was "old man", not because I'm a Joined Trill

but because that was apparently how I acted, how I came across. My physical problems probably played into that; with what I've now learnt is probably fibromyalgia, I started suffering great fatigue, stiffness, aches and pains, and I simply didn't have the energy to be in any way an active person.
To be honest, I feel somewhat "cheated" of my youth in that regard. When I hear older people speak of how they miss the energy and freedom of their younger years, it saddens me, because I don't have that now. And on top of that - and really not meaning to turn this into a woeful moan, so sorry

- my psychological and self-identity issues left me feeling like my life was essentially over. That I was burnt out, that I'd had my run and it hadn't worked out, and now there was only the wait for death. It's most frustrating to be waiting for death at age 18, because it seems so very far away. But I was so tired, so beaten down, I'd lost faith in everything and was basically wallowing in near-total apathy. I still managed to work hard enough to win me much favour from my university tutors and to graduate easily. But that was more a compulsion than an actual desire.
At the same time as I felt (and feel) so old, I also felt (feel) incredibly infantile. Partly because emotional memories are so vivid for me, I still feel trapped in a state of young childhood - frustrated, under the power and control of forces I can't stand up to. I sometimes respond poorly to stress, etc, because it's difficult not to feel as I did then. Like many of the posters here (indeed, like many people in general), the economic situation means that even with the backing of the country's top university I have little hope of finding work that will let me leave home or feel in control of my own life. And because I can't escape the sense that I'm pressed in by the same forces and attitudes that defined my stressful childhood, I find that I still "fall back" into being that child. In fact, I would say that sometimes I honestly do respond to things like a young child would - with the ultimate irony that when I was actually a young child I'd never have acted that way. The 22-year-old me has thrown more tantrums than the 3-year-old me.
I've tried to turn my perceptions around, to tell myself that I'm an adult, but that I also have a whole life ahead of me, that I can climb out of my current identity and enjoy myself, make something worthwhile. That maybe in 10 years time I'll be in a better place, and that I'm lucky enough to have "10 years later" as almost a guarantee (within reason). I just need to "grow up", and I don't mean that in a self-patronizing way. I mean I need to overcome the paralysis that defined my childhood and adolescence, the fear of expressing myself lest it invite censure and make me feel worthless. That's a difficult journey to make, though.