Another question about modeling...Please Help me figure this out!?

Okay soo i want to be a model. If I start now as in like in the next two years-ish (I'm 14 now) then that'll get me closer to being able to do runways. Today my boyfriend's mom was talking to her dad's girlfriend (kind of confusing, I know) about me taking good pictures. Then she said to me that she knows a modeling agency in a town close to where I live because she helped one of her friends get a job there. I really want to check it out, but of course I need to talk with my mom about it but I don't know how to bring it up to her. Any advice on how to talk with my mom about this? She's not the easiest person for me to talk to and she'll be asking questions like why I want this so badly, and blah blah blah things. Also if I'm going to model I need to be fit, but I have a terrible time staying on a work out scheduale and find it easier to just not eat but i really want to work out instead and eat healthy..if you have any advice on this, too, would be wonderfully awsome! (*: