How can i propose a girl?to be my lover.need a clue on how to,help i wanna know how.?

they is this girl i wanna start dating,we new each on the chating site and letter we met face to face.she lives just in the next neighbourhood.she is really kinda owesome and cute,i like her big time..please help with your best manifesto that a girl would never neglect.i want her to be my girlfrend,but i dont know where too start from.please help me how should i propose her?what words should i tell her?just want to win over her heart and let her love me back.please help,am 17 and she is 16years old.