Description about.... ???

Hello. The man, woman, boy, girl... (the person) about i'm going to make the description is unknown, I won't say who he/she is, so you have to guess (if you want).
I know to this person since I was 3 or 4. He/she was very small, wrinkled and ugly. Last a few days he was still small, but now he/she was a little fat and he was laughing all time for anything. Now, he/she is quite high, he/she isn't fat and he/she never laughs, he/she has blue eyes and his/her hair is disheveled, because he never combs it.
There are days that he/she's very boring because he/she is grumbling all time("Ñañaña, I have a lot of homework. Ñañaña, I hate school. Ñañaña, now I have to play guitar"), but are days that he/she is fun and you can speak and laugh with him (unfortunately, he/she is the second form only with a few persons).
Although this person is shy, if you speak with him and you get to known him/her, you can be a good friend.