When I was your age (I'm 16) I was about 125 and 5'5".
Although it really depends on different factors, such as how much muscle you have.
Currently working on:
Princess Kenny -- South Park
Roxy Lalonde Purple Dress -- Homestuck
Trisha Cappeletti -- MPGiS
Princess Ariel -- The Little Mermaid
My favorite cosplays:
Brittnay Matthews -- MPGiS
Mom Lalonde -- Homestuck
Tohru Honda -- Fruits Basket