Gym or Home With Friend?

[Briana]

So i'm starting High School in August, and im 13 and weight 160lbs. haha yeah im a fatass i know it and i aint really embarrased to say it. Anyways i wanna loose about 40lbs during the summer so I can look awesome when I go to High School also because in about a year and a half im going to be a dama in a quincenera of my very close friend. And i wanted to know if I should go to the gym and pay $600.00 for 1 year and get a personal trainer. or should i stay home and work out with the few equpiment I have in my house and on the weekends my friend coming over to work out with me too? And i also wanted to know if it is possible to loose 40lbs. in 2 months? other details are: 13 years old, 160lbs, 5'1. Haha and thanks again