the Rule of Thumb for newbies is to see well reviewed ladies.  This means ladies with at least 5-6 reviews by established reviewers (at least the same number of reviews but over a period of time--say a minimum of 9 months.

This decreases the likelihood of LE troubles.  Keep in mind, there is no such thing as a sure thing.

Your bare minimum should be 15 positive reviews. anything less, then you should pass it up.

Avoid any providers that only do outcalls. Most hotels will have a 18 year old age minimum. Many of them have a 21 year old minimum. If you see her at a incall at a hotel, and she has good reviews, then chances are you'll be fine.

Be careful on the age, especially if going to meet at a hotel. Check for reviews and in conversation let her know you're a newbie, but don't be taken advantage of, use your head, if it doesn't feel right, go with your gut.