Hi,
I like a girl in my school, I'm 14.
Can anybody tell me how to propose her in a manner that she agrees :P

Propose what?

Not marriage, I hope. You are too young. Pregnancy is not a reason for a 14 year old to propose. And not to be crass, but you have no proof that you are the one who got her pregnant. What proof do you even have yet that she is pregnant? Try to calm down and PLEASE find a trusted adult you know well.

Look your only 14 try exploring a little bit. Then if you really like her tell it to her face. You might be afraid but it might be worn it.