Is it not a bit strange that I'm still so childish?

It's a bit random, but lately I've been reflecting on how I am and why there are certain elements of my personality - and I realised, it seems I'm just childish. In almost every way. Which is odd, because as an actual child I was always intellectually mature and quite responsible even if I was sensitive and childish otherwise - and at 15 I'm still the same. It seems like other than in intellect and logic, I haven't grown at all - I have difficulty controlling my emotional outbursts, I get angry, offended and sulky really easily and I'm a bit of a baby socially - I feel left out and lonely easily and I thrive on attention, wilt with a lack of it. I have to try very hard to control my reactions and hide my excessive childishness in these reactions from others, especially in school. I'm not confident in myself or my choices; I need approval of my friends or whoever is around before I can do anything, and responsibility scares me even if it's just like I've been asked to give a message to a certain teacher, for example. I need to be almost forced to do things like coursework to start quickly and easily and I always procrastinate; I can't stop playing games or any other hobbies to do even important things until the very last minute and I get upset and stressed with so much ease - I can never feel better until I'm totally reured and comforted like a little kid. I'm a serious perfectionist but I also lack perseverance totally - if something doesn't go right the first time I try, it's hard to get me to stop being irritated/sad and to try again. Honestly, I find it a bit alarming and I'm sure it's not normal in the slightest. Is there really not anything I can do about this?