Now she's on holiday, Jamie can have up to five "castings" a day. She travels all over London just so model agents can look at her for a couple of minutes to see if she's got the "look" they're after.
Jamie's had castings for magazines like Sugar, pop videos and some top fashion names.
"I do get a bit nervous before castings, especially if it involves acting," she admitted. "I did one the other day when I had to dress as a cowgirl and lasso a man who was supposed to be the bull. I'm quite a shy person so I sometimes get nervous."
Despite her success, Jamie's not letting it go to her head. She's going to study four A-levels in the evenings from September, and will carry on modelling in the daytime.
"I want to carry on my education," she said. "I really love art and English. But I already know modelling is what I want to do. I just love it."
And the camera obviously loves her too!
Jamie is doing a model diary for CBBC Newsround Online, starting next week.
Click back here to read all her gossip from behind the scenes.