regarding the start up of garage band.

i have the garage band app pre installed on my iphone 5s gold 32 gb,as of now i dont have the wifi connection .when i clicked on the app.it showed me 100 mb download and two option were their to download wifi and mobile data...due to no wifi connection i clicked on mobile data which was my 2g connection the i pressed the home screen button..later when i noticed something is wrong ..i clicked on the garage band app but it not showing it it just bumps and shuts..i dont whts the prblm is anyone can help pls ??