OK, so I have looked for a long time but hesitant to start with my first provider. I want to so badly, but scared about repurcussions if something "follows" later. For those of you who have, how do you know the girl is disease free and will not stalk you later? Stupid, but honestly important questions.

Why do you think a provider would want to stalk YOU.  Are you George Clooney? I am pretty sure they have better things to do with their time than stalk a quasi, wanna-be hobbyist.
 As for disease free... there is always a chance, but remember, the provider is equally concerned about contracting a disease. Precautions are taken, yet there is some risk involved. If you aren't comfortable with that then this isn't a hobby you should consider.