How can I convince my mom that I need a "bridge" camera?

Just in case you guys didn’t know, a bridge camera is in between a point and shoot camera and a DSLR. I would really love to be a photographer when I get older, and I plan on taking college courses for it. I would like this to be my career, (or, at least, a very, very active hobby of mine). My ancient Kodak point and shoot camera broke over six months ago, and I’ve been pining after this camera since October. I chose this camera because it’s as inexpensive as possible for what I want, but it still has many features of a DSLR camera, which I don’t think I’m ready for yet. My mom has agreed to buy it for me when her income tax return check comes in. However, for me, that’s not good enough. I really want her to know why I need this type of a camera over a point and shoot, because I’m very, very passionate and obsessed with photography. She doesn’t understand why I can’t just get a good point and shoot camera. How can I make her understand why this is a much better choice for me?