As a Dom (not professional, though), let me throw in my 2 cents...
Take it as signing any contract. Read it, make sure nothing stupid is agreed to. I had a friend who came across the country (leaving her kids in the care of her ex-husband) to devote herself to a Dominant she met...only to be screwed over by him in a few months. Unfortunately, she also agreed to turn over the handling of finances/property/etc to him.
It all depends on how valuable it is to you. You know that she will push your limits...hell, that's most of the fun, right? Did you have a serious chat about your limits, expectations, etc...? You'd probably want to. If she cares (and, yes, we Dominants do care for our subbies), she'll take it seriously. If she refuses to budge, requiring your blind, unswerving, and total trust...well, personally, I keep day to day life and sexual life separate. I expect my subs to submit sexually, but also expect them to make their own decisions at the supermarket!
As long as you *don't* do anything irreversable (like signing away all your possessions), you can always back out...it will probably break your relationship, but so it goes. Good luck.