Here is the thing OP, hobbying is a risky business... You can do EVERYTHING right(not talk about money, specify you want nothing but time, etc.) and you can still be arrested just for showing up!! As much as spending a few hours in jail sucks, getting convicted is much more damaging...
I'm no Perry Mason or Johnny Cochran BUT if you follow a few simple rules then I can guarantee that the DA will have a hard time prosecuting you if you're ever arrested...
1) NEVER, under any circumstances, discuss on the phone or in person about what you want or details about the service... If she ever does then either end the discussin or walk away...
2) if you ever are arrested and you've said NOTHING about any services that you want, then STFU!!!! Do not talk or answer any questions!!! Invoke your right to remain silent and ask for a lawyer... LE officers are very slick and will try to make it sound like they are your friends and that they are nice guys... DON'T fall for their bullshit and make it easier for them to make a case for the DA... STFU!! Don't even say "I haven't done anything wrong"!!! Just say I'd like to talk to a lawyer or I don't have anything to say... I've actually seen the cuffs go on people who have invoked their right to remain silent, don't give the police any evidence, and then released when LE realizes, the chances of getting a conviction are slim to none... Many people have been arrested and convicted due to incriminating themselves!! Don't be one of them and just STFU!!
3) RESEARCH!!! As others have stated check out her reviews AND longevity... Also if she is relatively new and have several reviews by "hobbyist" who are also new or have only one or two reviews, then you might want to avoid her until more trusted hobbiest see and review her...
4) Last but not least if you're going to gamble on backpage then trust your instincts... If you come across pics that seem TGTBT then most likely she is... I mean if someone looks like a 9 or a 10 and you can't find any reviews on eccie or other sites then I'd stay away...
Again this hobby is not without risk but if you're smart and take some of the advice given, the chances of you getting into trouble are VERY slim... Enjoy and have fun!!