The other side of me is appearing

I don't know why but i feel tired out of the sudden. I will start daydreaming or thinking about things i should be thinking at that time... The girl side of me is appearing and the over-mature side has already appeared since i come to secondary school. I don't like to say nice stuffs to others, i becaome hard-hearted and i don't know why am i so hard for these 3 years. Example like today, when they are singing birthday song, i purposely went to buy drink for puay suan. It is not that i don't want to sing the birthday song but i feel very uneasy about it. I just don't like it. Even saying happy birthday to a person can be very uneasy to me. I hope my friends will forgive me if i never say happy birthday or praise you guys. I am just changing at this age. Maybe i am the one who is over-mature. Well but the girl side of me, i will not elaborate. I will just keep it to myself and maybe one day i just will say it out so that i can feel more relief and relax. Maybe i can start finding a person to talk to such that i won't feel so bad after stuffing everything in my heart.