1150 sounds like a NORMAL weight for a 2 year old female to me.

They don't usually reach 1500 grams until they are 3 years old, unless they're really power-fed. (A few individuals grow super-fast, but it's fairly rare).
If she LOOKS skinny, then feed her every 5 days for a while, and she'll soon not look skinny--provided she doesn't have any underlying health problems, such as parasites. (Always a good thing to test for in a new acquisition). I don't agree with breeding female balls under 3 years of age, personally, I think they need the extra year to reach true adulthood even if they're large at age 2. (My thought is, if they are 1500 grams at 2 years old, they'll be a LOT bigger at age 3, and probably lay larger clutches).