How do you start out a story?? ?

I love writing stories but I never know how to start them. They always sound so corny. If you could give me some ideas to start off my story that'd be great(: it's about a 17 year old wealthy girl who falls for a poor 18 year old high school drop out. & she becomes pregnant with his baby. The girl is really friendly & the guy is mysterious. I think I want the story to start near the end of her school year. Thank you in advance!!(: