The problem with that being...?
> I supose I'm too immature for my age.
No, most girls around your age are very immature. At least you admitting it and discussing this whole issue in 4-ch is a step ahead of most.
And if you know you're immature, then you have walked the first step towards fixing it. You know what's wrong, now stop doing it, and you'll have a better, happier life!