Rebbecca was seventeen when she came to Chiswick as an articled pupil.
However, if you'd like to emphasize her status as an articled student going to Chiswick:
When Rebbecca was seventeen, she was brought over as an articled pupil to Chiswick.
The rest of your paragraph is difficult to decipher. We could work together to make it comprehensible.
Student or Learner