Slim body, 'chunky' face?

This is probably the biggest issue I have with my self confidence...appearance wise. I am about 5''8', and 135 pounds...I'm pretty slim, if not athletically built. However, I have a very 'chunky', or full face. It's frustrating for many reasons. I'm twenty-years-old but still look much younger, which I guess in the future this won't be a drawback, but right now it's inconvenient and annoying. Also, this seems to be a physically unattractive quality. The 'hot' actresses of today (Megan Fox, Olivia Wilde) all have very defined cheekbones and chiseled jaws. Me...not so much. I guess what I'm asking is..will I grow out of my 'fat face' (is it baby fat) or are there exercises I can do? Any suggestions? Thank you!